Psycholinguistics

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Psycholinguistics

Psycholinguistics or psychology of language is the study of the interrelation between linguistic factors and psychological aspects. The discipline is mainly concerned with the mechanisms by which language is processed and represented in the mind and brain; that is, the psychological and neurobiological factors that enable humans to acquire, use, comprehend, and produce language.

Psycholinguistics is concerned with the cognitive faculties and processes that are necessary to produce the grammatical constructions of language. It is also concerned with the perception of these constructions by a listener.

Initial forays into psycholinguistics were in the philosophical and educational fields, mainly due to their location in departments other than applied sciences (e.g., cohesive data on how the human brain functioned). Modern research makes use of biology, neuroscience, cognitive science, linguistics, and information science to study how the mind-brain processes language, and less so the known processes of social sciences, human development, communication theories, and infant development, among others.

There are several subdisciplines with non-invasive techniques for studying the neurological workings of the brain. For example, neurolinguistics has become a field in its own right, and developmental psycholinguistics, as a branch of psycholinguistics, concerns itself with a child's ability to learn language.

Areas of study

Psycholinguistics is an interdisciplinary field that consists of researchers from a variety of different backgrounds, including psychology, cognitive science, linguistics, speech and language pathology, and discourse analysis. Psycholinguists study how people acquire and use language, according to the following main ways:

1. language acquisition: how do children acquire language?
2. language comprehension: how do people comprehend language?
3. language production: how do people produce language?
4. second language acquisition: how do people who already know one language acquire another one?

A researcher interested in language comprehension may study word recognition during reading, to examine the processes involved in the extraction of orthographic, morphological, phonological, and semantic information from patterns in printed text. A researcher interested in language production might study how words are prepared to be spoken starting from the conceptual or semantic level (this concerns connotation, and possibly can be examined through the conceptual framework concerned with the semantic differential). Developmental psycholinguists study infants' and children's ability to learn and process language.

Psycholinguistics further divide their studies according to the different components that make up human language.

Linguistics-related areas include:

• Phonetics and phonology are the study of speech sounds. Within psycholinguistics, research focuses on how the brain processes and understands these sounds.
• Morphology is the study of word structures, especially between related words (such as dog and dogs) and the formation of words based on rules (such as plural formation).
• Syntax is the study of how words are combined to form sentences.
• Semantics deals with the meaning of words and sentences. Where syntax is concerned with the formal structure of sentences, semantics deals with the actual meaning of sentences.
• Pragmatics is concerned with the role of context in the interpretation of meaning.
• Linguistic relativity is a principle suggesting that the structure of a language influences its speakers' worldview or cognition, and thus individuals' languages determine or shape their perceptions of the world.

History

In seeking to understand the properties of language acquisition, psycholinguistics has roots in debates regarding innate versus acquired behaviors (both in biology and psychology). For some time, the concept of an innate trait was something that was not recognized in studying the psychology of the individual. However, with the redefinition of innateness as time progressed, behaviors considered innate could once again be analyzed as behaviors that interacted with the psychological aspect of an individual. After the diminished popularity of the behaviorist model, ethology reemerged as a leading train of thought within psychology, allowing the subject of language, an innate human behavior, to be examined once more within the scope of psychology.

Origin of "psycholinguistics"

The theoretical framework for psycholinguistics began to be developed before the end of the 19th century as the "Psychology of Language". The work of Edward Thorndike and Frederic Bartlett laid the foundations of what would come to be known as the science of psycholinguistics. In 1936 Jacob Kantor, a prominent psychologist at the time, used the term "psycholinguistic" as a description within his book An Objective Psychology of Grammar.

However, the term "psycholinguistics" only came into widespread usage in 1946 when Kantor's student Nicholas Pronko published an article entitled "Psycholinguistics: A Review". Pronko's desire was to unify myriad related theoretical approaches under a single name. Psycholinguistics was used for the first time to talk about an interdisciplinary science "that could be coherent", as well as being the title of Psycholinguistics: A Survey of Theory and Research Problems, a 1954 book by Charles E. Osgood and Thomas A. Sebeok.

Theories

Language acquisition

Main article: Language acquisition

Though there is still much debate, there are two primary theories on childhood language acquisition:

• the behaviorist perspective, whereby all language must be learned by the child; and
• the innatist perspective, which believes that the abstract system of language cannot be learned, but that humans possess an innate language faculty or access to what has been called "universal grammar".

The innatist perspective began in 1959 with Noam Chomsky's highly critical review of B.F. Skinner's Verbal Behavior (1957). This review helped start what has been called the cognitive revolution in psychology. Chomsky posited that humans possess a special, innate ability for language, and that complex syntactic features, such as recursion, are "hard-wired" in the brain. These abilities are thought to be beyond the grasp of even the most intelligent and social non-humans. When Chomsky asserted that children acquiring a language have a vast search space to explore among all possible human grammars, there was no evidence that children received sufficient input to learn all the rules of their language. Hence, there must be some other innate mechanism that endows humans with the ability to learn language. According to the "innateness hypothesis", such a language faculty is what defines human language and makes that faculty different from even the most sophisticated forms of animal communication.

The field of linguistics and psycholinguistics has since been defined by pro-and-con reactions to Chomsky. The view in favor of Chomsky still holds that the human ability to use language (specifically the ability to use recursion) is qualitatively different from any sort of animal ability.

The view that language must be learned was especially popular before 1960 and is well represented by the mentalistic theories of Jean Piaget and the empiricist Rudolf Carnap. Likewise, the behaviorist school of psychology puts forth the point of view that language is a behavior shaped by conditioned response; hence it is learned. The view that language can be learned has had a recent resurgence inspired by emergentism. This view challenges the "innate" view as scientifically unfalsifiable; that is to say, it cannot be tested. With the increase in computer technology since the 1980s, researchers have been able to simulate language acquisition using neural network models.

Language comprehension

Main article: Language comprehension

The structures and uses of language are related to the formation of ontological insights. Some see this system as "structured cooperation between language-users" who use conceptual and semantic difference in order to exchange meaning and knowledge, as well as give meaning to language, thereby examining and describing "semantic processes bound by a 'stopping' constraint which are not cases of ordinary deferring." Deferring is normally done for a reason, and a rational person is always disposed to defer if there is good reason.

The theory of the "semantic differential" supposes universal distinctions, such as:

• Typicality: that included scales such as "regular–rare", "typical–exclusive";
• Reality: "imaginary–real", "evident–fantastic", "abstract–concrete";
• Complexity: "complex–simple", "unlimited–limited", "mysterious–usual";
• Improvement or Organization: "regular–spasmodic", "constant–changeable", "organized–disorganized", "precise–indefinite";
• Stimulation: "interesting–boring", "trivial–new".

Reading

Main article: Reading

One question in the realm of language comprehension is how people understand sentences as they read (i.e., sentence processing). Experimental research has spawned several theories about the architecture and mechanisms of sentence comprehension. These theories are typically concerned with the types of information, contained in the sentence, that the reader can use to build meaning and the point at which that information becomes available to the reader. Issues such as "modular" versus "interactive" processing have been theoretical divides in the field.

A modular view of sentence processing assumes that the stages involved in reading a sentence function independently as separate modules. These modules have limited interaction with one another. For example, one influential theory of sentence processing, the "garden-path theory", states that syntactic analysis takes place first. Under this theory, as the reader is reading a sentence, he or she creates the simplest structure possible, to minimize effort and cognitive load. This is done without any input from semantic analysis or context-dependent information. Hence, in the sentence "The evidence examined by the lawyer turned out to be unreliable", by the time the reader gets to the word "examined" he or she has committed to a reading of the sentence in which the evidence is examining something because it is the simplest parsing. This commitment is made even though it results in an implausible situation: evidence cannot examine something. Under this "syntax first" theory, semantic information is processed at a later stage. It is only later that the reader will recognize that he or she needs to revise the initial parsing into one in which "the evidence" is being examined. In this example, readers typically recognize their mistake by the time they reach "by the lawyer" and must go back and reevaluate the sentence. This reanalysis is costly and contributes to slower reading times. A 2024 study found that during self-paced reading tasks, participants progressively read faster and recalled information more accurately, suggesting that task adaptation is driven by learning processes rather than by declining motivation.

In contrast to the modular view, an interactive theory of sentence processing, such as a constraint-based lexical approach assumes that all available information contained within a sentence can be processed at any time. Under an interactive view, the semantics of a sentence (such as plausibility) can come into play early on to help determine the structure of a sentence. Hence, in the sentence above, the reader would be able to make use of plausibility information in order to assume that "the evidence" is being examined instead of doing the examining. There are data to support both modular and interactive views; which view is correct is debatable.

When reading, saccades can cause the mind to skip over words because it does not see them as important to the sentence, and the mind completely omits it from the sentence or supplies the wrong word in its stead. This can be seen in "Paris in the the Spring". This is a common psychological test, where the mind will often skip the second "the", especially when there is a line break in between the two.

Language production

Main article: Language production

Language production refers to how people produce language, either in written or spoken form, in a way that conveys meanings comprehensible to others. One of the most effective ways to explain the way people represent meanings using rule-governed languages is by observing and analyzing instances of speech errors, which include speech disfluencies like false starts, repetition, reformulation and constant pauses in between words or sentences, as well as slips of the tongue, like-blendings, substitutions, exchanges (e.g. Spoonerism), and various pronunciation errors.

These speech errors have significant implications for understanding how language is produced, in that they reflect that:

1. Speech is not planned in advance: speech errors such as substitution and exchanges show that one does not plan their entire sentence before they speak. Rather, their language faculty is constantly tapped during the speech production process. This is accounted for by the limitation of working memory. In particular, errors involving exchanges imply that one plans one's sentence ahead but only with regard to its significant ideas (e.g. the words that constitute the core meaning) and only to a certain extent.
2. Lexicon is organized semantically and phonologically: substitution and pronunciation errors show that lexicon is organized not only by its meaning, but also its form.
3. Morphologically complex words are assembled: errors involving blending within a word reflect that there seems to be a rule governing the construction of words in production (and also likely in mental lexicon). In other words, speakers generate the morphologically complex words by merging morphemes rather than retrieving them as chunks.

It is useful to differentiate between three separate phases of language production:

1. conceptualization: "determining what to say";
2. formulation: "translating the intention to say something into linguistic form";
3. execution: "the detailed articulatory planning and articulation itself".

Psycholinguistic research has largely concerned itself with the study of formulation because the conceptualization phase remains largely elusive and mysterious.

Cognition and linguistic relativity

Main article: Linguistic relativity

Linguistic relativity, often associated with the Sapir-Whorf hypothesis, posits that the structure of a language influences cognitive processes and world perception. While early formulations of this idea were largely speculative, modern psycholinguistic research has reframed it as a testable hypothesis within the broader study of language and thought.

Contemporary approaches to linguistic relativity are often discussed into following perspectives:

1. Weak linguistic relativity – Language biases cognitive tendencies but does not determine thought. This perspective aligns with experimental findings showing that linguistic structures influence perception, memory, and categorization probabilistically rather than absolutely.
2. Language as a cognitive tool – Language serves as a scaffolding mechanism for cognitive processes, actively shaping mental representations in domains such as space, time, and color perception.

A key refinement of linguistic relativity is Slobin’s (1996) "Thinking for Speaking" hypothesis, which argues that language influences cognition most strongly when individuals prepare to communicate. Unlike traditional views of linguistic relativity, which suggest that language passively shapes thought, "Thinking for Speaking" proposes that speakers actively engage with linguistic categories and structures while constructing utterances.

From a psycholinguistic standpoint, research on linguistic relativity intersects with conceptual representations, perceptual learning, and cognitive flexibility. Experimental studies have tested these ideas by examining how speakers of different languages categorize the world differently. For instance, cross-linguistic comparisons in spatial cognition reveal that languages with absolute spatial frames (e.g., Guugu Yimithirr) encourage speakers to encode space differently than languages with relative spatial frames (e.g., English).

In the domain of bilingual cognition, psycholinguistic research suggests that bilinguals may experience cognitive restructuring, where language context modulates perception and categorization. Recent studies indicate that bilinguals can flexibly switch between different conceptual systems, depending on the language they are using, particularly in domains such as motion perception, event construal, and time perception.

Overall, linguistic relativity in psycholinguistics is no longer seen as a rigid determinism of thought by language, but rather as a gradual, experience-based modulation of cognition by linguistic structures. This perspective has led to a shift from a purely linguistic hypothesis to an integrative cognitive science framework incorporating evidence from experimental psychology, neuroscience, and computational modeling.

Methodologies

Behavioral tasks

Many of the experiments conducted in psycholinguistics, especially early on, are behavioral in nature. In these types of studies, subjects are presented with linguistic stimuli and asked to respond. For example, they may be asked to make a judgment about a word (lexical decision), reproduce the stimulus, or say a visually presented word aloud. Reaction times to respond to the stimuli (usually on the order of milliseconds) and proportion of correct responses are the most often employed measures of performance in behavioral tasks. Such experiments often take advantage of priming effects, whereby a "priming" word or phrase appearing in the experiment can speed up the lexical decision for a related "target" word later.

As an example of how behavioral methods can be used in psycholinguistics research, Fischler (1977) investigated word encoding, using a lexical-decision task. He asked participants to make decisions about whether two strings of letters were English words. Sometimes the strings would be actual English words requiring a "yes" response, and other times they would be non-words requiring a "no" response. A subset of the licit words were related semantically (e.g., cat–dog) while others were unrelated (e.g., bread–stem). Fischler found that related word pairs were responded to faster, compared to unrelated word pairs, which suggests that semantic relatedness can facilitate word encoding.

Eye-movements

Recently, eye tracking has been used to study online language processing. Beginning with Rayner (1978), the importance of understanding eye-movements during reading was established. Later, Tanenhaus et al. (1995) used a visual-world paradigm to study the cognitive processes related to spoken language. Assuming that eye movements are closely linked to the current focus of attention, language processing can be studied by monitoring eye movements while a subject is listening to spoken language.

Language production errors

Main article: Speech error

The analysis of systematic errors in speech, as well as the writing and typing of language, can provide evidence of the process that has generated it. Errors of speech, in particular, grant insight into how the mind produces language while a speaker is mid-utterance. Speech errors tend to occur in the lexical, morpheme, and phoneme encoding steps of language production, as seen by the ways errors can manifest themselves. 

The types of speech errors, with some examples, include:

• Substitutions (phoneme and lexical) — replacing a sound with an unrelated sound, or a word with its antonym, saying such as "verbal outfit" instead of "verbal output", or "He rode his bike tomorrow" instead of "...yesterday", respectively;
• Blends — mixing two synonyms and saying "my stummy hurts" in place of either "stomach" or "tummy";
• Exchanges (phoneme [aka spoonerisms] and morpheme) — swapping two onset sounds or two root words, and saying "You hissed my mystery lectures" instead of "You missed my history lectures", or "They're Turking talkish" instead of "They're talking Turkish", respectively;
• Morpheme shifts — moving a function morpheme such as "-ly" or "-ed" to a different word and saying "easy enoughly" instead of "easily enough",
• Perseveration — incorrectly starting a word with a sound that was a part of the previous utterance, such as saying "John gave the goy a ball" instead of "John gave the boy a ball";
• Anticipation — replacing a sound with one that belongs later in the utterance, such as saying "She drank a cot cup of tea" instead of "She drank a hot cup of tea".

Speech errors will usually occur in the stages that involve lexical, morpheme, or phoneme encoding, and usually not in the first step of semantic encoding. This can be attributed to a speaker still conjuring the idea of what to say; and unless he changes his mind, can not be mistaken for what he wanted to say.

Neuroimaging

Main article: Neurolinguistics

Until the recent advent of non-invasive medical techniques, brain surgery was the preferred way for language researchers to discover how language affects the brain. For example, severing the corpus callosum (the bundle of nerves that connects the two hemispheres of the brain) was at one time a treatment for some forms of epilepsy. Researchers could then study the ways in which the comprehension and production of language were affected by such drastic surgery. When an illness made brain surgery necessary, language researchers had an opportunity to pursue their research.

Newer, non-invasive techniques now include brain imaging by positron emission tomography (PET); functional magnetic resonance imaging (fMRI); event-related potentials (ERPs) in electroencephalography (EEG) and magnetoencephalography (MEG); and transcranial magnetic stimulation (TMS). Brain imaging techniques vary in their spatial and temporal resolutions (fMRI has a resolution of a few thousand neurons per pixel, and ERP has millisecond accuracy). Each methodology has advantages and disadvantages for the study of psycholinguistics.

Computational modeling

Computational modelling, such as the DRC model of reading and word recognition proposed by Max Coltheart and colleagues, is another methodology, which refers to the practice of setting up cognitive models in the form of executable computer programs. Such programs are useful because they require theorists to be explicit in their hypotheses and because they can be used to generate accurate predictions for theoretical models that are so complex that discursive analysis is unreliable. Other examples of computational modelling are McClelland and Elman's TRACE model of speech perception and Franklin Chang's Dual-Path model of sentence production.

Psychophysical approach

The psychophysical approach in psycholinguistics applies quantitative measurement techniques to investigate how linguistic structures influence perception and cognitive processes. Unlike traditional behavioral experiments that rely on categorical judgments or reaction times, psychophysical methods allow for precise, continuous measurement of perceptual and cognitive changes induced by language.

A key advantage of psychophysical methods is their ability to capture fine-grained perceptual effects of language. For instance, studies on color perception have used just-noticeable difference (JND) thresholds to show that speakers of languages with finer color distinctions (e.g., Russian for light vs. dark blue) exhibit heightened perceptual sensitivity at linguistic category boundaries.

Recent psychophysical research has also been applied to time perception, investigating how bilinguals process temporal information differently based on their linguistic background. Using psychophysical duration estimation tasks, researchers have demonstrated that bilinguals may exhibit different time perception patterns depending on which language they are using at the moment.

These methods provide insights into how linguistic categories shape cognitive processing at a perceptual level, distinguishing between effects that arise from language structure itself and those that emerge from general cognitive mechanisms. As psycholinguistics continues to integrate computational and neuroscientific approaches, psychophysical techniques offer a bridge between language processing and sensory cognition, refining our understanding of how language interacts with perception.

Areas for further research

Psycholinguistics is concerned with the nature of the processes that the brain undergoes in order to comprehend and produce language. For example, the cohort model seeks to describe how words are retrieved from the mental lexicon when an individual hears or sees linguistic input. Using new non-invasive imaging techniques, recent research seeks to shed light on the areas of the brain involved in language processing.

Another unanswered question in psycholinguistics is whether the human ability to use syntax originates from innate mental structures or social interaction, and whether or not some animals can be taught the syntax of human language.

Two other major subfields of psycholinguistics investigate first language acquisition, the process by which infants acquire language, and second language acquisition. It is much more difficult for adults to acquire second languages than it is for infants to learn their first language (infants are able to learn more than one native language easily). Thus, sensitive periods may exist during which language can be learned readily. A great deal of research in psycholinguistics focuses on how this ability develops and diminishes over time. It also seems to be the case that the more languages one knows, the easier it is to learn more.

The field of aphasiology deals with language deficits that arise because of brain damage. Studies in aphasiology can offer both advances in therapy for individuals suffering from aphasia and further insight into how the brain processes language.

Mirror neuron

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Mirror_neuron

A mirror neuron is a neuron that fires both when an animal acts and when the animal observes the same action performed by another. Thus, the neuron "mirrors" the behavior of the other, as though the observer were itself acting. Mirror neurons are not always physiologically distinct from other types of neurons in the brain; their main differentiating factor is their response patterns. By this definition, such neurons have been directly observed in humans and other primates, as well as in birds.

In humans, brain activity consistent with that of mirror neurons has been found in the premotor cortex, the supplementary motor area, the primary somatosensory cortex, and the inferior parietal cortex. The function of the mirror system in humans is a subject of much speculation. Birds have been shown to have imitative resonance behaviors and neurological evidence suggests the presence of some form of mirroring system. To date, no widely accepted neural or computational models have been put forward to describe how mirror neuron activity supports cognitive functions.

The subject of mirror neurons continues to generate intense debate. In 2014, Philosophical Transactions of the Royal Society B published a special issue entirely devoted to mirror neuron research. Some researchers speculate that mirror systems may simulate observed actions, and thus contribute to theory of mind skills, while others relate mirror neurons to language abilities. Neuroscientists such as Marco Iacoboni have argued that mirror neuron systems in the human brain help humans understand the actions and intentions of other people. In addition, Iacoboni has argued that mirror neurons are the neural basis of the human capacity for emotions such as empathy.

Discovery

In the 1980s and 1990s, neurophysiologists Giacomo Rizzolatti, Giuseppe Di Pellegrino, Luciano Fadiga, Leonardo Fogassi, and Vittorio Gallese at the University of Parma placed electrodes in the ventral premotor cortex of the macaque monkey to study neurons specialized in the control of hand and mouth actions; for example, taking hold of an object and manipulating it. During each experiment, the researchers allowed the monkey to reach for pieces of food, and recorded from single neurons in the monkey's brain, thus measuring the neuron's response to certain movements. They found that some neurons responded when the monkey observed a person picking up a piece of food, and also when the monkey itself picked up the food. The discovery was initially submitted to Nature, but was rejected for its "lack of general interest" before being published in a less competitive journal.

A few years later, the same group published another empirical paper, discussing the role of the mirror-neuron system in action recognition, and proposing that the human Broca's area was the homologue region of the monkey ventral premotor cortex. While these papers reported the presence of mirror neurons responding to hand actions, a subsequent study by Pier Francesco Ferrari and colleagues described the presence of mirror neurons responding to mouth actions and facial gestures.

Further experiments confirmed that about 10% of neurons in the monkey inferior frontal and inferior parietal cortex have "mirror" properties and give similar responses to performed hand actions and observed actions. In 2002 Christian Keysers and colleagues reported that, in both humans and monkeys, the mirror system also responds to the sound of actions.

Reports on mirror neurons have been widely published and confirmed with mirror neurons found in both inferior frontal and inferior parietal regions of the brain. Recently, evidence from functional neuroimaging strongly suggests that humans have similar mirror neurons systems: researchers have identified brain regions which respond during both action and observation of action. Not surprisingly, these brain regions include those found in the macaque monkey. However, functional magnetic resonance imaging (fMRI) can examine the entire brain at once and suggests that a much wider network of brain areas shows mirror properties in humans than previously thought. These additional areas include the somatosensory cortex and are thought to make the observer feel what it feels like to move in the observed way.

Origin

Many implicitly assume that the mirroring function of mirror neurons is due primarily to heritable genetic factors and that the genetic predisposition to develop mirror neurons evolved because they facilitate action understanding. In contrast, a number of theoretical accounts argue that mirror neurons could simply emerge due to learned associations, including the Hebbian Theory, the Associative Learning Theory, and Canalization.

In monkeys

Neonatal (newborn) macaque imitating facial expressions

The first animal in which researchers have studied mirror neurons individually is the macaque monkey. In these monkeys, mirror neurons are found in the inferior frontal gyrus (region F5) and the inferior parietal lobule.

Mirror neurons are believed to mediate the understanding of other animals' behaviour. For example, a mirror neuron which fires when the monkey rips a piece of paper would also fire when the monkey sees a person rip paper, or hears paper ripping (without visual cues). These properties have led researchers to believe that mirror neurons encode abstract concepts of actions like 'ripping paper', whether the action is performed by the monkey or another animal.

The function of mirror neurons in macaques remains unknown. Adult macaques do not seem to learn by imitation. Recent experiments by Ferrari and colleagues suggest that infant macaques can imitate a human's face movements, though only as neonates and during a limited temporal window. Even if it has not yet been empirically demonstrated, it has been proposed that mirror neurons cause this behaviour and other imitative phenomena. Indeed, there is limited understanding of the degree to which monkeys show imitative behaviour.

In adult monkeys, mirror neurons may enable the monkey to understand what another monkey is doing, or to recognize the other monkey's action.

In rodents

A number of studies have shown that rats and mice show signs of distress while witnessing another rodent receive footshocks. The group of Christian Keysers's recorded from neurons while rats experienced pain or witnessed the pain of others, and has revealed the presence of pain mirror neurons in the rat's anterior cingulate cortex, i.e. neurons that respond both while an animal experiences pain and while witnessing the pain of others. Deactivating this region of the cingulate cortex led to reduced emotional contagion in the rats, so that observer rats showed reduced distress while witnessing another rat experience pain. The homologous part of the anterior cingulate cortex has been associated with empathy for pain in humans, suggesting a homology between the systems involved in emotional contagion in rodents and empathy/emotional contagion for pain in humans.

In humans

Diagram of the brain, showing the locations of the frontal and parietal lobes of the cerebrum, viewed from the left. The inferior frontal lobe is the lower part of the blue area, and the superior parietal lobe is the upper part of the yellow area.

It is not normally possible to study single neurons in the human brain, so most evidence for mirror neurons in humans is indirect. Brain imaging experiments using functional magnetic resonance imaging (fMRI) have shown that the human inferior frontal cortex and superior parietal lobe are active when the person performs an action and also when the person sees another individual performing an action. It has been suggested that these brain regions contain mirror neurons, and they have been defined as the human mirror neuron system. More recent experiments have shown that even at the level of single participants, scanned using fMRI, large areas containing multiple fMRI voxels increase their activity both during the observation and execution of actions.

Neuropsychological studies looking at lesion areas that cause action knowledge, pantomime interpretation, and biological motion perception deficits have pointed to a causal link between the integrity of the inferior frontal gyrus and these behaviours. Transcranial magnetic stimulation studies have confirmed this as well. These results indicate the activation in mirror neuron related areas are unlikely to be just epiphenomenal.

A study published in April 2010 reports recordings from single neurons with mirror properties in the human brain. Mukamel et al. (Current Biology, 2010) recorded from the brains of 21 patients who were being treated at Ronald Reagan UCLA Medical Center for intractable epilepsy. The patients had been implanted with intracranial depth electrodes to identify seizure foci for potential surgical treatment. Electrode location was based solely on clinical criteria; the researchers, with the patients' consent, used the same electrodes to "piggyback" their research. The researchers found a small number of neurons that fired or showed their greatest activity both when the individual performed a task and when they observed a task. Other neurons had anti-mirror properties: they responded when the participant performed an action, but were inhibited when the participant saw that action.

The mirror neurons found were located in the supplementary motor area and medial temporal cortex (other brain regions were not sampled). For purely practical reasons, these regions are not the same as those in which mirror neurons had been recorded from in the monkey: researchers in Parma were studying the ventral premotor cortex and the associated inferior parietal lobe, two regions in which epilepsy rarely occurs, and hence, single cell recordings in these regions are not usually done in humans. On the other hand, no one has to date looked for mirror neurons in the supplementary motor area or the medial temporal lobe in the monkey. Together, this therefore does not suggest that humans and monkeys have mirror neurons in different locations, but rather that they may have mirror neurons both in the ventral premotor cortex and inferior parietal lobe, where they have been recorded in the monkey, and in the supplementary motor areas and medial temporal lobe, where they have been recorded from in human – especially because detailed human fMRI analyses suggest activity compatible with the presence of mirror neurons in all these regions.

Another study has suggested that human beings do not necessarily have more mirror neurons than monkeys, but instead that there is a core set of mirror neurons used in action observation and execution. However, for other proposed functions of mirror neurons the mirror system may have the ability to recruit other areas of the brain when doing its auditory, somatosensory, and affective components.

Development

Human infant data using eye-tracking measures suggest that the mirror neuron system develops before 12 months of age and that this system may help human infants understand other people's actions. A critical question concerns how mirror neurons acquire mirror properties. Two closely related models postulate that mirror neurons are trained through Hebbian or Associative learning (see Associative Sequence Learning). However, if premotor neurons need to be trained by action in order to acquire mirror properties, it is unclear how newborn babies are able to mimic the facial gestures of another person (imitation of unseen actions), as suggested by the work of Meltzoff and Moore. One possibility is that the sight of tongue protrusion recruits an innate releasing mechanism in neonates. Careful analysis suggests that 'imitation' of this single gesture may account for almost all reports of facial mimicry by new-born infants.

Possible functions

Understanding intentions

Many studies link mirror neurons to understanding goals and intentions. Fogassi et al. (2005) recorded the activity of 41 mirror neurons in the inferior parietal lobe (IPL) of two rhesus macaques. The IPL has long been recognized as an association cortex that integrates sensory information. The monkeys watched an experimenter either grasp an apple and bring it to his mouth or grasp an object and place it in a cup.

• In total, 15 mirror neurons fired vigorously when the monkey observed the "grasp-to-eat" motion, but registered no activity while exposed to the "grasp-to-place" condition.
• For 4 other mirror neurons, the reverse held true: they activated in response to the experimenter eventually placing the apple in the cup but not to eating it.

Only the type of action, and not the kinematic force with which models manipulated objects, determined neuron activity. It was also significant that neurons fired before the monkey observed the human model starting the second motor act (bringing the object to the mouth or placing it in a cup). Therefore, IPL neurons "code the same act (grasping) in a different way according to the final goal of the action in which the act is embedded." They may furnish a neural basis for predicting another individual's subsequent actions and inferring intention.

Understanding intention can be broken down into various stages such as body perception and action identification. These stages correlate with various regions of the brain, for example for body parts/shapes match with the extrastriate and fusiform body areas of the brain. The action itself is identified and facilitated by the mirror neuron system. Action understanding falls into two different processing levels, the mirror neuron system and the mentalizing system. Expected actions are primarily processed by the mirror neuron system and unexpected actions are processed by a combination of the mirror neuron system and the mentalizing system.

Learning facilitation

Another possible function of mirror neurons would be facilitation of learning. The mirror neurons code the concrete representation of the action, i.e., the representation that would be activated if the observer acted. This would allow us to simulate (to repeat internally) the observed action implicitly (in the brain) to collect our own motor programs of observed actions and to get ready to reproduce the actions later. It is implicit training. Due to this, the observer will produce the action explicitly (in his/her behavior) with agility and finesse. This happens due to associative learning processes. The more frequently a synaptic connection is activated, the stronger it becomes.

Empathy

Stephanie Preston and Frans de Waal, Jean Decety, and Vittorio Gallese and Christian Keysers have independently argued that the mirror neuron system is involved in empathy. A large number of experiments using fMRI, electroencephalography (EEG) and magnetoencephalography (MEG) have shown that certain brain regions (in particular the anterior insula, anterior cingulate cortex, and inferior frontal cortex) are active when people experience an emotion (disgust, happiness, pain, etc.) and when they see another person experiencing an emotion. David Freedberg and Vittorio Gallese have also put forward the idea that this function of the mirror neuron system is crucial for aesthetic experiences. Nevertheless, an experiment aimed at investigating the activity of mirror neurons in empathy conducted by Soukayna Bekkali and Peter Enticott at the University of Deakin yielded a different result. After analyzing the report's data, they came up with two conclusions about motor empathy and emotional empathy. First, there is no relationship between motor empathy and the activity of mirror neurons. Second, there is only weak evidence of these neurons' activity in the inferior frontal gyrus (IFG), and no evidence of emotional empathy associated with mirror neurons in key brain regions (inferior parietal lobule: IPL). In other words, there has not been an exact conclusion about the role of mirror neurons in empathy and if they are essential for human empathy. However, these brain regions are not quite the same as the ones which mirror hand actions, and mirror neurons for emotional states or empathy have not yet been described in monkeys.

In a recent study, done in 2022, sixteen hand actions were given for each assignment. The assignment pictured both an activity word phase and the intended word phase. The hand actions were selected in "trails" each introduced twice. One of the times was with a matching phase and the other time was with a misleading word phase. The action words were depicted in two to three words with each beginning with the word "to". For instance, "to point" (action) or "to spin" (intention).

Participants were expected to answer whether the correct word phase matched the corresponding action or intention word. The word phase had to be answered within 3000 ms, with a 1000 ms black screen between each image. The black screens purpose was for an adequate amount of time in between responses. Participants pressed on the keyboard "x" or "m" to indicate their responses in a yes/no format.

Christian Keysers at the Social Brain Lab and colleagues have shown that people who are more empathic according to self-report questionnaires have stronger activations both in the mirror system for hand actions and the mirror system for emotions, providing more direct support for the idea that the mirror system is linked to empathy. Some researchers observed that the human mirror system does not passively respond to the observation of actions but is influenced by the mindset of the observer. Researchers observed the link of the mirror neurons during empathetic engagement in patient care.

Studies in rats have shown that the anterior cingulate cortex contains mirror neurons for pain, i.e. neurons responding both during the first-hand experience of pain and while witnessing the pain of others, and inhibition of this region leads to reduced emotional contagion in rats and mice, and reduced aversion towards harming others. This provides causal evidence for a link between pain mirror neurons, and emotional contagion and prosocial behavior, two phenomena associated with empathy, in rodents. That brain activity in the homologous brain region is associated with individual variability in empathy in humans suggests that a similar mechanism may be at play across mammals.

Human self awareness

V. S. Ramachandran has speculated that mirror neurons may provide the neurological basis of human self-awareness. In an essay written for the Edge Foundation in 2009 Ramachandran gave the following explanation of his theory: "... I also speculated that these neurons can not only help simulate other people's behavior but can be turned 'inward'—as it were—to create second-order representations or meta-representations of your own earlier brain processes. This could be the neural basis of introspection, and of the reciprocity of self awareness and other awareness. There is obviously a chicken-or-egg question here as to which evolved first, but... The main point is that the two co-evolved, mutually enriching each other to create the mature representation of self that characterizes modern humans."

Language

In humans, functional MRI studies have reported finding areas homologous to the monkey mirror neuron system in the inferior frontal cortex, close to Broca's area, one of the hypothesized language regions of the brain. This has led to suggestions that human language evolved from a gesture performance/understanding system implemented in mirror neurons. Mirror neurons have been said to have the potential to provide a mechanism for action-understanding, imitation-learning, and the simulation of other people's behaviour. This hypothesis is supported by some cytoarchitectonic homologies between monkey premotor area F5 and human Broca's area. Rates of vocabulary expansion link to the ability of children to vocally mirror non-words and so to acquire the new word pronunciations. Such speech repetition occurs automatically, fast and separately in the brain to speech perception. Moreover, such vocal imitation can occur without comprehension such as in speech shadowing and echolalia.

Further evidence for this link comes from a recent study in which the brain activity of two participants was measured using fMRI while they were gesturing words to each other using hand gestures with a game of charades – a modality that some have suggested might represent the evolutionary precursor of human language. Analysis of the data using Granger Causality revealed that the mirror-neuron system of the observer indeed reflects the pattern of activity in the motor system of the sender, supporting the idea that the motor concept associated with the words is indeed transmitted from one brain to another using the mirror system

The mirror neuron system seems to be inherently inadequate to play any role in syntax, given that this definitory property of human languages which is implemented in hierarchical recursive structure is flattened into linear sequences of phonemes making the recursive structure not accessible to sensory detection

Automatic imitation

The term is commonly used to refer to cases in which an individual, having observed a body movement, unintentionally performs a similar body movement or alters the way that a body movement is performed. Automatic imitation rarely involves overt execution of matching responses. Instead the effects typically consist of reaction time, rather than accuracy, differences between compatible and incompatible trials. Research reveals that the existence of automatic imitation, which is a covert form of imitation, is distinct from spatial compatibility. It also indicates that, although automatic imitation is subject to input modulation by attentional processes, and output modulation by inhibitory processes, it is mediated by learned, long-term sensorimotor associations that cannot be altered directly by intentional processes. Many researchers believe that automatic imitation is mediated by the mirror neuron system. Additionally, there are data that demonstrate that our postural control is impaired when people listen to sentences about other actions. For example, if the task is to maintain posture, people do it worse when they listen to sentences like this: "I get up, put on my slippers, go to the bathroom." This phenomenon may be due to the fact that during action perception there is similar motor cortex activation as if a human being performed the same action (mirror neurons system).

Motor mimicry

In contrast with automatic imitation, motor mimicry is observed in (1) naturalistic social situations and (2) via measures of action frequency within a session rather than measures of speed and/or accuracy within trials.

The integration of research on motor mimicry and automatic imitation could reveal plausible indications that these phenomena depend on the same psychological and neural processes. Preliminary evidence however comes from studies showing that social priming has similar effects on motor mimicry.

Nevertheless, the similarities between automatic imitation, mirror effects, and motor mimicry have led some researchers to propose that automatic imitation is mediated by the mirror neuron system and that it is a tightly controlled laboratory equivalent of the motor mimicry observed in naturalistic social contexts. If true, then automatic imitation can be used as a tool to investigate how the mirror neuron system contributes to cognitive functioning and how motor mimicry promotes prosocial attitudes and behavior.

Meta-analysis of imitation studies in humans suggest that there is enough evidence of mirror system activation during imitation that mirror neuron involvement is likely, even though no published studies have recorded the activities of singular neurons. However, it is likely insufficient for motor imitation. Studies show that regions of the frontal and parietal lobes that extend beyond the classical mirror system are equally activated during imitation. This suggests that other areas, along with the mirror system are crucial to imitation behaviors.

Autism

It has also been proposed that problems with the mirror neuron system may underlie cognitive disorders, particularly autism. However the connection between mirror neuron dysfunction and autism is tentative and it remains to be demonstrated how mirror neurons are related to many of the important characteristics of autism.

Some researchers claim there is a link between mirror neuron deficiency and autism. EEG recordings from motor areas are suppressed when someone watches another person move, a signal that may relate to mirror neuron system. Additionally, the correlation can be measured with eye-movement tracking of biological motions, together with EEG recordings, mu suppression index can be calculated. This suppression was less in children with autism. Although these findings have been replicated by several groups, other studies have not found evidence of a dysfunctional mirror neuron system in autism. In 2008, Oberman et al. published a research paper that presented conflicting EEG evidence. Oberman and Ramachandran found typical mu-suppression for familiar stimuli, but not for unfamiliar stimuli, leading them to conclude that the mirror neuron system of children with ASD (Autism Spectrum Disorder) was functional, but less sensitive than that of typical children. Based on the conflicting evidence presented by mu-wave suppression experiments, Patricia Churchland has cautioned that mu-wave suppression results cannot be used as a valid index for measuring the performance of mirror neuron systems. Recent research indicates that mirror neurons do not play a role in autism:

...no clear cut evidence emerges for a fundamental mirror system deficit in autism. Behavioural studies have shown that people with autism have a good understanding of action goals. Furthermore, two independent neuroimaging studies have reported that the parietal component of the mirror system is functioning typically in individuals with autism.

Some anatomical differences have been found in the mirror neuron related brain areas in adults with autism spectrum disorders, compared to non-autistic adults. All these cortical areas were thinner and the degree of thinning was correlated with autism symptom severity, a correlation nearly restricted to these brain regions. Based on these results, some researchers claim that autism is caused by impairments in the mirror neuron system, leading to disabilities in social skills, imitation, empathy and theory of mind.

Many researchers have pointed out that the "broken mirrors" theory of autism is overly simplistic, and mirror neurons alone cannot explain the differences found in individuals with autism. First of all, as noted above, none of these studies were direct measures of mirror neuron activity - in other words fMRI activity or EEG rhythm suppression do not unequivocally index mirror neurons. Dinstein and colleagues found normal mirror neuron activity in people with autism using fMRI. In individuals with autism, deficits in intention understanding, action understanding and biological motion perception (the key functions of mirror neurons) are not always found, or are task dependent. Today, very few people believe an all-or-nothing problem with the mirror system can underlie autism. Instead, "additional research needs to be done, and more caution should be used when reaching out to the media."

Research from 2010 concluded that autistic individuals do not exhibit mirror neuron dysfunction, although the small sample size limits the extent to which these results can be generalized. A more recent review argued there was not enough neurological evidence to support this “broken-mirror theory” of autism.

Theory of mind

In Philosophy of mind, mirror neurons have become the primary rallying call of simulation theorists concerning our "theory of mind." "Theory of mind" refers to our ability to infer another person's mental state (i.e., beliefs and desires) from experiences or their behaviour.

There are several competing models which attempt to account for our theory of mind; the most notable in relation to mirror neurons is simulation theory. According to simulation theory, theory of mind is available because we subconsciously empathize with the person we're observing and, accounting for relevant differences, imagine what we would desire and believe in that scenario. Mirror neurons have been interpreted as the mechanism by which we simulate others in order to better understand them, and therefore their discovery has been taken by some as a validation of simulation theory (which appeared a decade before the discovery of mirror neurons). More recently, Theory of Mind and Simulation have been seen as complementary systems, with different developmental time courses.

At the neuronal-level, in a 2015 study by Keren Haroush and Ziv Williams using jointly interacting primates performing an iterated prisoner's dilemma game, the authors identified neurons in the anterior cingulate cortex that selectively predicted an opponent's yet unknown decisions or covert state of mind. These "other-predictive neurons" differentiated between self and other decisions and were uniquely sensitive to social context, but they did not encode the opponent's observed actions or receipt of reward. These cingulate cells may therefore importantly complement the function of mirror neurons by providing additional information about other social agents that is not immediately observable or known.

Sex differences

A series of recent studies conducted by Yawei Cheng, using a variety of neurophysiological measures, including MEG, spinal reflex excitability, electroencephalography, have documented the presence of a gender difference in the human mirror neuron system, with female participants exhibiting stronger motor resonance than male participants.

In another study, sex-based differences among mirror neuron mechanisms was reinforced in that the data showed enhanced empathetic ability in females relative to males. During an emotional social interaction, females showed a greater ability in emotional perspective taking than did males when interacting with another person face-to-face. However, in the study, data showed that when it came to recognizing the emotions of others, all participants' abilities were very similar and there was no key difference between the male and female subjects.

Sleep paralysis

Baland Jalal and V. S. Ramachandran have hypothesized that the mirror neuron system is important in giving rise to the intruder hallucination and out-of-body experiences during sleep paralysis. According to this theory, sleep paralysis leads to disinhibition of the mirror neuron system, paving the way for hallucinations of human-like shadowy beings. The deafferentation of sensory information during sleep paralysis is proposed as the mechanism for such mirror neuron disinhibition. The authors suggest that their hypothesis on the role of the mirror neuron system could be tested:

"These ideas could be explored using neuroimaging, to examine the selective activation of brain regions associated with mirror neuron activity, when the individual is hallucinating an intruder or having an out-of-body experience during sleep paralysis ."

Mirror neuron function, psychosis, and empathy in schizophrenia

Recent research, which measured mu-wave suppression, suggests that mirror neuron activity is positively correlated with psychotic symptoms (i.e., greater mu suppression/mirror neuron activity was highest among subjects with the greater severity of psychotic symptoms). Researchers concluded that "higher mirror neuron activity may be the underpinning of schizophrenia sensory gating deficits and may contribute to sensory misattributions particularly in response to socially relevant stimuli, and be a putative mechanism for delusions and hallucinations."

Doubts concerning mirror neurons

Although some in the scientific community have expressed excitement about the discovery of mirror neurons, there are scientists who have expressed doubts about both the existence and role of mirror neurons in humans. The consensus today seems to be that the importance of so-called mirror neurons is widely overblown. According to scientists such as Hickok, Pascolo, and Dinstein, it is not clear whether mirror neurons really form a distinct class of cells (as opposed to an occasional phenomenon seen in cells that have other functions), and whether mirror activity is a distinct type of response or simply an artifact of an overall facilitation of the motor system.

In 2008, Ilan Dinstein et al. argued that the original analyses were unconvincing because they were based on qualitative descriptions of individual cell properties, and did not take into account the small number of strongly mirror-selective neurons in motor areas. Other scientists have argued that the measurements of neuron fire delay seem not to be compatible with standard reaction times, and pointed out that nobody has reported that an interruption of the motor areas in F5 would produce a decrease in action recognition. Critics of this argument have replied that these authors have missed human neuropsychological and TMS studies reporting disruption of these areas do indeed cause action deficits without affecting other kinds of perception.

In 2009, Lingnau et al. carried out an experiment in which they compared motor acts that were first observed and then executed to motor acts that were first executed and then observed. They concluded that there was a significant asymmetry between the two processes that indicated that mirror neurons do not exist in humans. They stated "Crucially, we found no signs of adaptation for motor acts that were first executed and then observed. Failure to find cross-modal adaptation for executed and observed motor acts is not compatible with the core assumption of mirror neuron theory, which holds that action recognition and understanding are based on motor simulation." However, in the same year, Kilner et al. showed that if goal directed actions are used as stimuli, both IPL and premotor regions show the repetition suppression between observation and execution that is predicted by mirror neurons.

In 2009, Greg Hickok published an extensive argument against the claim that mirror neurons are involved in action-understanding: "Eight Problems for the Mirror Neuron Theory of Action Understanding in Monkeys and Humans." He concluded that "The early hypothesis that these cells underlie action understanding is likewise an interesting and prima facie reasonable idea. However, despite its widespread acceptance, the proposal has never been adequately tested in monkeys, and in humans there is strong empirical evidence, in the form of physiological and neuropsychological (double-) dissociations, against the claim."

The mirror neurons can be activated only after the goal of the observed action has been attributed by other brain structures.

Vladimir Kosonogov sees another contradiction. The proponents of mirror neuron theory of action understanding postulate that the mirror neurons code the goals of others' actions because they are activated if the observed action is goal-directed. However, the mirror neurons are activated only when the observed action is goal-directed (object-directed action or a communicative gesture, which certainly has a goal too). How do they "know" that the definite action is goal-directed? At what stage of their activation do they detect a goal of the movement or its absence? In his opinion, the mirror neuron system can be activated only after the goal of the observed action is attributed by some other brain structures.

Neurophilosophers such as Patricia Churchland have expressed both scientific and philosophical objections to the theory that mirror neurons are responsible for understanding the intentions of others. In chapter 5 of her 2011 book, Braintrust, Churchland points out that the claim that mirror neurons are involved in understanding intentions (through simulating observed actions) is based on assumptions that are clouded by unresolved philosophical issues. She makes the argument that intentions are understood (coded) at a more complex level of neural activity than that of individual neurons. Churchland states that "A neuron, though computationally complex, is just a neuron. It is not an intelligent homunculus. If a neural network represents something complex, such as an intention [to insult], it must have the right input and be in the right place in the neural circuitry to do that."

Cecilia Heyes has advanced the theory that mirror neurons are the byproduct of associative learning as opposed to evolutionary adaptation. She argues that mirror neurons in humans are the product of social interaction and not an evolutionary adaptation for action-understanding. In particular, Heyes rejects the theory advanced by V.S. Ramachandran that mirror neurons have been "the driving force behind the great leap forward in human evolution."

Semiotics

Semiotics (/ˌsɛmiˈɒtɪks/ SEM-ee-OT-iks) is the systematic study of sign processes and the communication of meaning. In semiotics, a sign is defined as anything that communicates intentional and unintentional meaning or feelings to the sign's interpreter.

Semiosis is any activity, conduct, or process that involves signs. Signs often are communicated by verbal language, but also by gestures, or by other forms of language, e.g. artistic ones (music, painting, sculpture, etc.). Contemporary semiotics is a branch of science that generally studies meaning-making (whether communicated or not) and various types of knowledge.

Unlike linguistics, semiotics also studies non-linguistic sign systems. Semiotics includes the study of indication, designation, likeness, analogy, allegory, metonymy, metaphor, symbolism, signification, and communication.

Semiotics is frequently seen as having important anthropological and sociological dimensions. Some semioticians regard every cultural phenomenon as being able to be studied as communication. Semioticians also focus on the logical dimensions of semiotics, examining biological questions such as how organisms make predictions about, and adapt to, their semiotic niche in the world.

Fundamental semiotic theories take signs or sign systems as their object of study. Applied semiotics analyzes cultures and cultural artifacts according to the ways they construct meaning through their being signs. The communication of information in living organisms is covered in biosemiotics including zoosemiotics and phytosemiotics.

History and terminology

The importance of signs and signification has been recognized throughout much of the history of philosophy and psychology. The term derives from Ancient Greek σημειωτικός (sēmeiōtikós) 'observant of signs' (from σημεῖον (sēmeîon) 'a sign, mark, token'). For the Greeks, 'signs' (σημεῖον sēmeîon) occurred in the world of nature and 'symbols' (σύμβολον sýmbolon) in the world of culture. As such, Plato and Aristotle explored the relationship between signs and the world.

It would not be until Augustine of Hippo that the nature of the sign would be considered within a conventional system. Augustine introduced a thematic proposal for uniting the two under the notion of 'sign' (signum) as transcending the nature–culture divide and identifying symbols as no more than a species (or sub-species) of signum. A monograph study on this question was done by Manetti (1987). These theories have had a lasting effect in Western philosophy, especially through scholastic philosophy.

The general study of signs that began in Latin with Augustine culminated with the 1632 Tractatus de Signis of John Poinsot and then began anew in late modernity with the attempt in 1867 by Charles Sanders Peirce to draw up a "new list of categories". More recently Umberto Eco, in his Semiotics and the Philosophy of Language, has argued that semiotic theories are implicit in the work of most, perhaps all, major thinkers.

John Locke

John Locke (1690), himself a man of medicine, was familiar with this "semeiotics" as naming a specialized branch within medical science. In his personal library were two editions of Scapula's 1579 abridgement of Henricus Stephanus' Thesaurus Graecae Linguae, which listed σημειωτική as the name for 'diagnostics', the branch of medicine concerned with interpreting symptoms of disease ("symptomatology"). Physician and scholar Henry Stubbe (1670) had transliterated this term of specialized science into English precisely as "semeiotics", marking the first use of the term in English:

"...nor is there any thing to be relied upon in Physick, but an exact knowledge of medicinal phisiology (founded on observation, not principles), semeiotics, method of curing, and tried (not excogitated, not commanding) medicines...."

Locke would use the term sem(e)iotike in An Essay Concerning Human Understanding (book IV, chap. 21), in which he explains how science may be divided into three parts:

All that can fall within the compass of human understanding, being either, first, the nature of things, as they are in themselves, their relations, and their manner of operation: or, secondly, that which man himself ought to do, as a rational and voluntary agent, for the attainment of any end, especially happiness: or, thirdly, the ways and means whereby the knowledge of both the one and the other of these is attained and communicated; I think science may be divided properly into these three sorts.

Locke then elaborates on the nature of this third category, naming it Σημειωτική (Semeiotike), and explaining it as "the doctrine of signs" in the following terms:

Thirdly, the third branch [of sciences] may be termed σημειωτικὴ, or the doctrine of signs, the most usual whereof being words, it is aptly enough termed also Λογικὴ, logic; the business whereof is to consider the nature of signs the mind makes use of for the understanding of things, or conveying its knowledge to others.

Juri Lotman introduced Eastern Europe to semiotics and adopted Locke's coinage (Σημειωτική) as the name to subtitle his founding at the University of Tartu in Estonia in 1964 of the first semiotics journal, Sign Systems Studies.

Ferdinand de Saussure

Ferdinand de Saussure founded his semiotics, which he called semiology, in the social sciences:

It is...possible to conceive of a science which studies the role of signs as part of social life. It would form part of social psychology, and hence of general psychology. We shall call it semiology (from the Greek semeîon, 'sign'). It would investigate the nature of signs and the laws governing them. Since it does not yet exist, one cannot say for certain that it will exist. But it has a right to exist, a place ready for it in advance. Linguistics is only one branch of this general science. The laws which semiology will discover will be laws applicable in linguistics, and linguistics will thus be assigned to a clearly defined place in the field of human knowledge.

Thomas Sebeok would assimilate semiology to semiotics as a part to a whole, and was involved in choosing the name Semiotica for the first international journal devoted to the study of signs. Saussurean semiotics have exercised a great deal of influence on the schools of structuralism and post-structuralism. Jacques Derrida, for example, takes as his object the Saussurean relationship of signifier and signified, asserting that signifier and signified are not fixed, coining the expression différance, relating to the endless deferral of meaning, and to the absence of a "transcendent signified".

Charles Sanders Peirce

In the nineteenth century, Charles Sanders Peirce defined what he termed "semiotic" (which he would sometimes spell as "semeiotic") as the "quasi-necessary, or formal doctrine of signs," which abstracts "what must be the characters of all signs used by...an intelligence capable of learning by experience," and which is philosophical logic pursued in terms of signs and sign processes.

Peirce's perspective is considered as philosophical logic studied in terms of signs that are not always linguistic or artificial, and sign processes, modes of inference, and the inquiry process in general. The Peircean semiotic addresses not only the external communication mechanism, as per Saussure, but the internal representation machine, investigating sign processes, and modes of inference, as well as the whole inquiry process in general.

Peircean semiotic is triadic, including sign, object, interpretant, as opposed to the dyadic Saussurian tradition (signifier, signified). Peircean semiotics further subdivides each of the three triadic elements into three sub-types, positing the existence of signs that are symbols; semblances ("icons"); and "indices," i.e., signs that are such through a factual connection to their objects.

Peircean scholar and editor Max H. Fisch (1978) would claim that "semeiotic" was Peirce's own preferred rendering of Locke's σημιωτική. Charles W. Morris followed Peirce in using the term "semiotic" and in extending the discipline beyond human communication to animal learning and use of signals.

While the Saussurean semiotic is dyadic (sign/syntax, signal/semantics), the Peircean semiotic is triadic (sign, object, interpretant), being conceived as philosophical logic studied in terms of signs that are not always linguistic or artificial.

Peirce's list of categories

Peirce would aim to base his new list directly upon experience precisely as constituted by action of signs, in contrast with the list of Aristotle's categories which aimed to articulate within experience the dimension of being that is independent of experience and knowable as such, through human understanding.

The estimative powers of animals interpret the environment as sensed to form a "meaningful world" of objects, but the objects of this world (or Umwelt, in Jakob von Uexküll's term) consist exclusively of objects related to the animal as desirable (+), undesirable (–), or "safe to ignore" (0).

In contrast to this, human understanding adds to the animal Umwelt a relation of self-identity within objects which transforms objects experienced into 'things' as well as +, –, 0 objects. Thus, the generically animal objective world as Umwelt, becomes a species-specifically human objective world or Lebenswelt ('life-world'), wherein linguistic communication, rooted in the biologically underdetermined Innenwelt ('inner-world') of humans, makes possible the further dimension of cultural organization within the otherwise merely social organization of non-human animals whose powers of observation may deal only with directly sensible instances of objectivity.

This further point, that human culture depends upon language understood first of all not as communication, but as the biologically underdetermined aspect or feature of the human animal's Innenwelt, was originally clearly identified by Thomas A. Sebeok. Sebeok also played the central role in bringing Peirce's work to the center of the semiotic stage in the twentieth century, first with his expansion of the human use of signs (anthroposemiosis) to include also the generically animal sign-usage (zoösemiosis), then with his further expansion of semiosis to include the vegetative world (phytosemiosis). Such would initially be based on the work of Martin Krampen, but takes advantage of Peirce's point that an interpretant, as the third item within a sign relation, "need not be mental".

Peirce distinguished between the interpretant and the interpreter. The interpretant is the internal, mental representation that mediates between the object and its sign. The interpreter is the human who is creating the interpretant. Peirce's "interpretant" notion opened the way to understanding an action of signs beyond the realm of animal life (study of phytosemiosis + zoösemiosis + anthroposemiosis = biosemiotics), which was his first advance beyond Latin Age semiotics.

Other early theorists in the field of semiotics include Charles W. Morris. Writing in 1951, Jozef Maria Bochenski surveyed the field in this way: "Closely related to mathematical logic is the so-called semiotics (Charles Morris) which is now commonly employed by mathematical logicians. Semiotics is the theory of symbols and falls in three parts;

1. logical syntax, the theory of the mutual relations of symbols,
2. logical semantics, the theory of the relations between the symbol and what the symbol stands for, and
3. logical pragmatics, the relations between symbols, their meanings and the users of the symbols."

Max Black argued that the work of Bertrand Russell was seminal in the field.

Formulations and subfields

Color-coding hot- and cold-water faucets (taps) is common in many cultures but, as this example shows, the coding may be rendered meaningless because of context. The two faucets (taps) probably were sold as a coded set, but the code is unusable (and ignored), as there is a single water supply.

Semioticians classify signs or sign systems in relation to the way they are transmitted. This process of carrying meaning depends on the use of codes that may be the individual sounds or letters that humans use to form words, the body movements they make to show attitude or emotion, or even something as general as the clothes they wear. To coin a word to refer to a thing, the community must agree on a simple meaning (a denotative meaning) within their language, but that word can transmit that meaning only within the language's grammatical structures and codes. Codes also represent the values of the culture, and are able to add new shades of connotation to every aspect of life.

To explain the relationship between semiotics and communication studies, communication is defined as the process of transferring data and-or meaning from a source to a receiver. Hence, communication theorists construct models based on codes, media, and contexts to explain the biology, psychology, and mechanics involved. Both disciplines recognize that the technical process cannot be separated from the fact that the receiver must decode the data, i.e., be able to distinguish the data as salient, and make meaning out of it. This implies that there is a necessary overlap between semiotics and communication. Indeed, many of the concepts are shared, although in each field the emphasis is different. In Messages and Meanings: An Introduction to Semiotics, Marcel Danesi (1994) suggested that semioticians' priorities were to study signification first, and communication second. A more extreme view is offered by Jean-Jacques Nattiez who, as a musicologist, considered the theoretical study of communication irrelevant to his application of semiotics.

Syntactics

Semiotics differs from linguistics in that it generalizes the definition of a sign to encompass signs in any medium or sensory modality. Thus it broadens the range of sign systems and sign relations, and extends the definition of language in what amounts to its widest analogical or metaphorical sense. The branch of semiotics that deals with such formal relations between signs or expressions in abstraction from their signification and their interpreters, or—more generally—with formal properties of symbol systems (specifically, with reference to linguistic signs, syntax) is referred to as syntactics.

Peirce's definition of the term semiotic as the study of necessary features of signs also has the effect of distinguishing the discipline from linguistics as the study of contingent features that the world's languages happen to have acquired in the course of their evolutions. From a subjective standpoint, perhaps more difficult is the distinction between semiotics and the philosophy of language. In a sense, the difference lies between separate traditions rather than subjects. Different authors have called themselves "philosopher of language" or "semiotician." This difference does not match the separation between analytic and continental philosophy. On a closer look, there may be found some differences regarding subjects. Philosophy of language pays more attention to natural languages or to languages in general, while semiotics is deeply concerned with non-linguistic signification. Philosophy of language also bears connections to linguistics, while semiotics might appear closer to some of the humanities (including literary theory) and to cultural anthropology.

Cognitive semiotics

Semiosis or semeiosis is the process that forms meaning from any organism's apprehension of the world through signs. Scholars who have talked about semiosis in their subtheories of semiotics include C. S. Peirce, John Deely, and Umberto Eco. Cognitive semiotics is combining methods and theories developed in the disciplines of semiotics and the humanities, with providing new information into human signification and its manifestation in cultural practices. The research on cognitive semiotics brings together semiotics from linguistics, cognitive science, and related disciplines on a common meta-theoretical platform of concepts, methods, and shared data.

Cognitive semiotics may also be seen as the study of meaning-making by employing and integrating methods and theories developed in the cognitive sciences. This involves conceptual and textual analysis as well as experimental investigations. Cognitive semiotics initially was developed at the Center for Semiotics at Aarhus University (Denmark), with an important connection with the Center of Functionally Integrated Neuroscience (CFIN) at Aarhus Hospital. Amongst the prominent cognitive semioticians are Per Aage Brandt, Svend Østergaard, Peer Bundgård, Frederik Stjernfelt, Mikkel Wallentin, Kristian Tylén, Riccardo Fusaroli, and Jordan Zlatev. Zlatev later in co-operation with Göran Sonesson established CCS (Center for Cognitive Semiotics) at Lund University, Sweden.

Finite semiotics

Finite semiotics, developed by Cameron Shackell (2018, 2019), aims to unify existing theories of semiotics for application to the post-Baudrillardian world of ubiquitous technology. Its central move is to place the finiteness of thought at the root of semiotics and the sign as a secondary but fundamental analytical construct. The theory contends that the levels of reproduction that technology is bringing to human environments demands this reprioritisation if semiotics is to remain relevant in the face of effectively infinite signs. The shift in emphasis allows practical definitions of many core constructs in semiotics which Shackell has applied to areas such as human computer interaction, creativity theory, and a computational semiotics method for generating semiotic squares from digital texts.

Pictorial semiotics

Pictorial semiotics is intimately connected to art history and theory. It goes beyond them both in at least one fundamental way, however. While art history has limited its visual analysis to a small number of pictures that qualify as "works of art", pictorial semiotics focuses on the properties of pictures in a general sense, and on how the artistic conventions of images can be interpreted through pictorial codes. Pictorial codes are the way in which viewers of pictorial representations seem automatically to decipher the artistic conventions of images by being unconsciously familiar with them.

According to Göran Sonesson, a Swedish semiotician, pictures can be analyzed by three models: the narrative model, which concentrates on the relationship between pictures and time in a chronological manner as in a comic strip; the rhetoric model, which compares pictures with different devices as in a metaphor; and the Laokoon model, which considers the limits and constraints of pictorial expressions by comparing textual mediums that utilize time with visual mediums that utilize space.

The break from traditional art history and theory—as well as from other major streams of semiotic analysis—leaves open a wide variety of possibilities for pictorial semiotics. Some influences have been drawn from phenomenological analysis, cognitive psychology, structuralist, and cognitivist linguistics, and visual anthropology and sociology.

Globalization

Studies have shown that semiotics may be used to make or break a brand. Culture codes strongly influence whether a population likes or dislikes a brand's marketing, especially internationally. If the company is unaware of a culture's codes, it runs the risk of failing in its marketing. Globalization has caused the development of a global consumer culture where products have similar associations, whether positive or negative, across numerous markets.

Mistranslations may lead to instances of "Engrish" or "Chinglish" terms for unintentionally humorous cross-cultural slogans intended to be understood in English. When translating surveys, the same symbol may mean different things in the source and target language thus leading to potential errors. For example, the symbol of "x" is used to mark a response in English language surveys but "x" usually means 'no' in the Chinese convention. This may be caused by a sign that, in Peirce's terms, mistakenly indexes or symbolizes something in one culture, that it does not in another. In other words, it creates a connotation that is culturally-bound, and that violates some culture code. Theorists who have studied humor (such as Schopenhauer) suggest that contradiction or incongruity creates absurdity and therefore, humor. Violating a culture code creates this construct of ridiculousness for the culture that owns the code. Intentional humor also may fail cross-culturally because jokes are not on code for the receiving culture.

A good example of branding according to cultural code is Disney's international theme park business. Disney fits well with Japan's cultural code because the Japanese value "cuteness", politeness, and gift-giving as part of their culture code; Tokyo Disneyland sells the most souvenirs of any Disney theme park. In contrast, Disneyland Paris failed when it launched as Euro Disney because the company did not research the codes underlying European culture. Its storybook retelling of European folktales was taken as elitist and insulting, and the strict appearance standards that it had for employees resulted in discrimination lawsuits in France. Disney souvenirs were perceived as cheap trinkets. The park was a financial failure because its code violated the expectations of European culture in ways that were offensive.

However, some researchers have suggested that it is possible to successfully pass a sign perceived as a cultural icon, such as the logos for Coca-Cola or McDonald's, from one culture to another. This may be accomplished if the sign is migrated from a more economically developed to a less developed culture. The intentional association of a product with another culture has been called "foreign consumer culture positioning" (FCCP). Products also may be marketed using global trends or culture codes, for example, saving time in a busy world; but even these may be fine-tuned for specific cultures.

Research also found that, as airline industry brandings grow and become more international their logos become more symbolic and less iconic. The iconicity and symbolism of a sign depends on the cultural convention and are, on that ground, in relation with each other. If the cultural convention has greater influence on the sign, the signs get more symbolic value.

Semiotics of dreaming

The flexibility of human semiotics is well demonstrated in dreams. Sigmund Freud spelled out how meaning in dreams rests on a blend of images, affects, sounds, words, and kinesthetic sensations. In his chapter on "The Means of Representation," he showed how the most abstract sorts of meaning and logical relations can be represented by spatial relations. Two images in sequence may indicate "if this, then that" or "despite this, that." Freud thought the dream started with "dream thoughts" which were like logical, verbal sentences. He believed that the dream thought was in the nature of a taboo wish that would awaken the dreamer. In order to safeguard sleep, the midbrain converts and disguises the verbal dream thought into an imagistic form, through processes he called the "dream-work."

Introversive and extroversive semiosis in music

Kofi Agawu quotes the distinction made by Roman Jakobson between "introversive semiosis, a language which signifies itself," and extoversive semiosis, the referential component of the semiosis. Jakobson writes that introversive semiosis "is indissolubly linked with the esthetic function of sign systems and dominates not only music but also glossolalic poetry and nonrepresentational painting and sculpture", but Agawu uses the distinction mainly in music, proposing Schenkerian analysis as a path to introversive semiosis and topic theory as an example of extroversive semiosis. Jean-Jacques Nattiez makes the same distinction: "Roman Jakobson sees in music a semiotic system in which the 'introversive semiosis' – that is, the reference of each sonic element to the other elements to come — predominates over the 'extroversive semiosis' – or the referential link with the exterior world."

Musical topic theory

Semiotics can be directly linked to the ideals of musical topic theory, which traces patterns in musical figures throughout their prevalent context in order to assign some aspect of narrative, affect, or aesthetics to the gesture. Danuta Mirka's The Oxford Handbook of Topic Theory presents a holistic recognition and overview regarding the subject, offering insight into the development of the theory. In recognizing the indicative and symbolic elements of a musical line, gesture, or occurrence, one can gain a greater understanding of aspects regarding compositional intent and identity.

Philosopher Charles Pierce discusses the relationship of icons and indexes in relation to signification and semiotics. In doing so, he draws on the elements of various ideas, acts, or styles that can be translated into a different field. Whereas indexes consist of a contextual representation of a symbol, icons directly correlate with the object or gesture that is being referenced.

In his 1980 book Classic Music: Expression, Form, and Style, Leonard Ratner amends the conversation surrounding musical tropes—or "topics"—in order to create a collection of musical figures that have historically been indicative of a given style. Robert Hatten continues this conversation in Beethoven, Markedness, Correlation, and Interpretation (1994), in which he states that "richly coded style types which carry certain features linked to affect, class, and social occasion such as church styles, learned styles, and dance styles. In complex forms these topics mingle, providing a basis for musical allusion."

List of subfields

Subfields that have sprouted out of semiotics include, but are not limited to, the following:

• Biosemiotics: the study of semiotic processes at all levels of biology, or a semiotic study of living systems (e.g., Copenhagen–Tartu School). Annual meetings ("Gatherings in Biosemiotics") have been held since 2001.
• Semiotic anthropology and anthropological semantics.
• Cognitive semiotics: the study of meaning-making by employing and integrating methods and theories developed in the cognitive sciences. This involves conceptual and textual analysis as well as experimental investigations. Cognitive semiotics initially was developed at the Center for Semiotics at Aarhus University (Denmark), with an important connection with the Center of Functionally Integrated Neuroscience (CFIN) at Aarhus Hospital. Amongst the prominent cognitive semioticians are Per Aage Brandt, Svend Østergaard, Peer Bundgård, Frederik Stjernfelt, Mikkel Wallentin, Kristian Tylén, Riccardo Fusaroli, and Jordan Zlatev. Zlatev later in co-operation with Göran Sonesson established the Center for Cognitive Semiotics (CCS) at Lund University, Sweden.
• Comics semiotics: the study of the various codes and signs of comics and how they are understood.
• Computational semiotics: attempts to engineer the process of semiosis, in the study of and design for human–computer interaction or to mimic aspects of human cognition through artificial intelligence and knowledge representation.
• Cultural and literary semiotics: examines the literary world, the visual media, the mass media, and advertising in the work of writers such as Roland Barthes, Marcel Danesi, and Juri Lotman (e.g., Tartu–Moscow Semiotic School).
• Cybersemiotics: built on two already-generated interdisciplinary approaches: cybernetics and systems theory, including information theory and science; and Peircean semiotics, including phenomenology and pragmatic aspects of linguistics, attempts to make the two interdisciplinary paradigms—both going beyond mechanistic and pure constructivist ideas—complement each other in a common framework.
• Design semiotics or product semiotics: the study of the use of signs in the design of physical products; introduced by Martin Krampen and in a practitioner-oriented version by Rune Monö while teaching industrial design at the Institute of Design, Umeå University, Sweden.
• Ethnosemiotics: a disciplinary perspective which links semiotics concepts to ethnographic methods.
• Fashion semiotics
• Film semiotics: the study of the various codes and signs of film and how they are understood. Key figures include Christian Metz.
• Finite semiotics: an approach to the semiotics of technology developed by Cameron Shackell. It is used to both trace the effects of technology on human thought and to develop computational methods for performing semiotic analysis.
• Gregorian chant semiology: a current avenue of palaeographical research in Gregorian chant, which is revising the Solesmes school of interpretation.
• Hylosemiotics: an approach to semiotics that understands meaning as inference, which is developed through exploratory interaction with the physical world. It expands the concept of communication beyond a human-centered paradigm to include other sentient beings, such as animals, plants, bacteria, fungi, etc.
• Law and semiotics: one of the more accomplished publications in this field is the International Journal for the Semiotics of Law, published by International Association for the Semiotics of Law.
• Marketing semiotics (or commercial semiotics): an application of semiotic methods and semiotic thinking to the analysis and development of advertising and brand communications in cultural context. Key figures include Virginia Valentine, Malcolm Evans, Greg Rowland, Georgios Rossolatos. International annual conferences (Semiofest) have been held since 2012.
• Music semiology: the study of signs as they pertain to music on a variety of levels.
• Organisational semiotics: the study of semiotic processes in organizations (with strong ties to computational semiotics and human–computer interaction).
• Pictorial semiotics: an application of semiotic methods and semiotic thinking to art history.
• Semiotics of music videos: semiotics in popular music.
• Social semiotics: expands the interpretable semiotic landscape to include all cultural codes, such as in slang, fashion, tattoos, and advertising. Key figures include Roland Barthes, Michael Halliday, Bob Hodge, Chris William Martin and Christian Metz.
• Structuralism and post-structuralism in the work of Jacques Derrida, Michel Foucault, Louis Hjelmslev, Roman Jakobson, Jacques Lacan, Claude Lévi-Strauss, Roland Barthes, etc. Post-structuralism and semiotics are closely related in their approaches to language, meaning, and interpretation; their relationships, and focuses are on how signs—whether linguistic, visual, or cultural—function to convey meaning, and how those meanings can shift depending on context and interpretation.
• Theatre semiotics: an application of semiotic methods and semiotic thinking to theatre studies. Key figures include Keir Elam.
• Urban semiotics: the study of meaning in urban form as generated by signs, symbols, and their social connotations.
• Visual semiotics: analyses visual signs; prominent modern founders to this branch are Groupe μ and Göran Sonesson.
• Semiotics of photography: is the observation of symbolism used within photography.
• Artificial intelligence semiotics: the observation of visual symbols and the symbols' recognition by machine learning systems. The phrase was coined by Daniel Hoeg, founder of Semiotics Mobility, due to Semiotics Mobility's design and learning process for autonomous recognition and perception of symbols by neural networks. The phrase refers to machine learning and neural nets application of semiotic methods and semiotic machine learning to the analysis and development of robotics commands and instructions with subsystem communications in autonomous systems context.
• Semiotics of mathematics: the study of signs, symbols, sign systems and their structure, meaning and use in mathematics and mathematics education.

Notable semioticians

Signaling and communication between the Astatotilapia burtoni

Thomas Carlyle (1795–1881) ascribed great importance to symbols in a religious context, noting that all worship "must proceed by Symbols"; he propounded this theory in such works as "Characteristics" (1831), Sartor Resartus (1833–4), and On Heroes (1841), which have been retroactively recognized as containing semiotic theories.

Charles Sanders Peirce (1839–1914), a noted logician who founded philosophical pragmatism, defined semiosis as an irreducibly triadic process wherein something, as an object, logically determines or influences something as a sign to determine or influence something as an interpretation or interpretant, itself a sign, thus leading to further interpretants. Semiosis is logically structured to perpetuate itself. The object may be quality, fact, rule, or even fictional (Hamlet), and may be "immediate" to the sign, the object as represented in the sign, or "dynamic", the object as it really is, on which the immediate object is founded. The interpretant may be "immediate" to the sign, all that the sign immediately expresses, such as a word's usual meaning; or "dynamic", such as a state of agitation; or "final" or "normal", the ultimate ramifications of the sign about its object, to which inquiry taken far enough would be destined and with which any interpretant, at most, may coincide. His semiotic covered not only artificial, linguistic, and symbolic signs, but also semblances such as kindred sensible qualities, and indices such as reactions. He came c. 1903 to classify any sign by three interdependent trichotomies, intersecting to form ten (rather than 27) classes of sign. Signs also enter into various kinds of meaningful combinations; Peirce covered both semantic and syntactical issues in his speculative grammar. He regarded formal semiotic as logic per se and part of philosophy; as also encompassing study of arguments (hypothetical, deductive, and inductive) and inquiry's methods including pragmatism; and as allied to, but distinct from logic's pure mathematics. In addition to pragmatism, Peirce provided a definition of "sign" as a representamen, in order to bring out the fact that a sign is something that "represents" something else in order to suggest it (that is, "re-present" it) in some way:

A sign, or representamen, is something which stands to somebody for something in some respect or capacity. It addresses somebody, that is, creates in the mind of that person an equivalent sign. That sign which it creates I call the interpretant of the first sign. The sign stands for something, its object not in all respects, but in reference to a sort of idea.

Ferdinand de Saussure (1857–1913), the "father" of modern linguistics, proposed a dualistic notion of signs, relating the signifier as the form of the word or phrase uttered, to the signified as the mental concept. According to Saussure, the sign is completely arbitrary—i.e., there is no necessary connection between the sign and its meaning. This sets him apart from previous philosophers, such as Plato or the scholastics, who thought that there must be some connection between a signifier and the object it signifies. In his Course in General Linguistics, Saussure credits the American linguist William Dwight Whitney (1827–1894) with insisting on the arbitrary nature of the sign. Saussure's insistence on the arbitrariness of the sign also has influenced later philosophers and theorists such as Jacques Derrida, Roland Barthes, and Jean Baudrillard. Ferdinand de Saussure coined the term sémiologie while teaching his landmark "Course on General Linguistics" at the University of Geneva from 1906 to 1911. Saussure posited that no word is inherently meaningful. Rather a word is only a "signifier." i.e., the representation of something, and it must be combined in the brain with the "signified", or the thing itself, in order to form a meaning-imbued "sign." Saussure believed that dismantling signs was a real science, for in doing so we come to an empirical understanding of how humans synthesize physical stimuli into words and other abstract concepts.

Jakob von Uexküll (1864–1944) studied the sign processes in animals. He used the German word Umwelt, 'environment', to describe the individual's subjective world, and he invented the concept of functional circle (funktionskreis) as a general model of sign processes. In his Theory of Meaning (Bedeutungslehre, 1940), he described the semiotic approach to biology, thus establishing the field that now is called biosemiotics.

Valentin Voloshinov (1895–1936) was a Soviet-Russian linguist, whose work has been influential in the field of literary theory and Marxist theory of ideology. Written in the late 1920s in the USSR, Voloshinov's Marxism and the Philosophy of Language (Russian: Marksizm i Filosofiya Yazyka) developed a counter-Saussurean linguistics, which situated language use in social process rather than in an entirely decontextualized Saussurean langue.

Louis Hjelmslev (1899–1965) developed a formalist approach to Saussure's structuralist theories. His best known work is Prolegomena to a Theory of Language, which was expanded in Résumé of the Theory of Language, a formal development of glossematics, his scientific calculus of language.

Charles W. Morris (1901–1979): Unlike his mentor George Herbert Mead, Morris was a behaviorist and sympathetic to the Vienna Circle positivism of his colleague, Rudolf Carnap. Morris was accused by John Dewey of misreading Peirce.

In his 1938 Foundations of the Theory of Signs, he defined semiotics as grouped into three branches:

1. Syntactics/syntax: deals with the formal properties and interrelation of signs and symbols, without regard to meaning.
2. Semantics: deals with the formal structures of signs, particularly the relation between signs and the objects to which they apply (i.e. signs to their designata, and the objects that they may or do denote).
3. Pragmatics: deals with the biotic aspects of semiosis, including all the psychological, biological, and sociological phenomena that occur in the functioning of signs. Pragmatics is concerned with the relation between the sign system and sign-using agents or interpreters (i.e., the human or animal users).

Thure von Uexküll (1908–2004), the "father" of modern psychosomatic medicine, developed a diagnostic method based on semiotic and biosemiotic analyses.

Roland Barthes (1915–1980) was a French literary theorist and semiotician. He often would critique pieces of cultural material to expose how bourgeois society used them to impose its values upon others. For instance, the portrayal of wine drinking in French society as a robust and healthy habit would be a bourgeois ideal perception contradicted by certain realities (i.e. that wine can be unhealthy and inebriating). He found semiotics useful in conducting these critiques. Barthes explained that these bourgeois cultural myths were second-order signs, or connotations. A picture of a full, dark bottle is a sign, a signifier relating to a signified: a fermented, alcoholic beverage—wine. However, the bourgeois take this signified and apply their own emphasis to it, making "wine" a new signifier, this time relating to a new signified: the idea of healthy, robust, relaxing wine. Motivations for such manipulations vary from a desire to sell products to a simple desire to maintain the status quo. These insights brought Barthes very much in line with similar Marxist theory.

Algirdas Julien Greimas (1917–1992) developed a structural version of semiotics named, "generative semiotics", trying to shift the focus of discipline from signs to systems of signification. His theories develop the ideas of Saussure, Hjelmslev, Claude Lévi-Strauss, and Maurice Merleau-Ponty.

Thomas A. Sebeok (1920–2001), a student of Charles W. Morris, was a prolific and wide-ranging American semiotician. Although he insisted that animals are not capable of language, he expanded the purview of semiotics to include non-human signaling and communication systems, thus raising some of the issues addressed by philosophy of mind and coining the term zoosemiotics. Sebeok insisted that all communication was made possible by the relationship between an organism and the environment in which it lives. He also posed the equation between semiosis (the activity of interpreting signs) and life—a view that the Copenhagen-Tartu biosemiotic school has further developed.

Juri Lotman (1922–1993) was the founding member of the Tartu (or Tartu-Moscow) Semiotic School. He developed a semiotic approach to the study of culture—semiotics of culture—and established a communication model for the study of text semiotics. He also introduced the concept of the semiosphere. Among his Moscow colleagues were Vladimir Toporov, Vyacheslav Ivanov and Boris Uspensky.

Christian Metz (1931–1993) pioneered the application of Saussurean semiotics to film theory, applying syntagmatic analysis to scenes of films and grounding film semiotics in greater context.

Eliseo Verón (1935–2014) developed his "Social Discourse Theory" inspired in the Peircian conception of "Semiosis."

Groupe μ (founded 1967) developed a structural version of rhetorics, and the visual semiotics.

Umberto Eco (1932–2016) was an Italian novelist, semiotician and academic. He made a wider audience aware of semiotics by various publications, most notably A Theory of Semiotics and his novel, The Name of the Rose, which includes (second to its plot) applied semiotic operations. His most important contributions to the field bear on interpretation, encyclopedia, and model reader. He also criticized in several works (A theory of semiotics, La struttura assente, Le signe, La production de signes) the "iconism" or "iconic signs" (taken from Peirce's most famous triadic relation, based on indexes, icons, and symbols), to which he proposed four modes of sign production: recognition, ostension, replica, and invention.

Julia Kristeva (born 1941), a student of Lucien Goldmann and Roland Barthes, Bulgarian-French semiotician, literary critic, psychoanalyst, feminist, and novelist. She uses psychoanalytical concepts together with the semiotics, distinguishing the two components in the signification, the symbolic and the semiotic. Kristeva also studies the representation of women and women's bodies in popular culture, such as horror films and has had a remarkable influence on feminism and feminist literary studies.

Michael Silverstein (1945–2020), a theoretician of semiotics and linguistic anthropology. Over the course of his career he created an original synthesis of research on the semiotics of communication, the sociology of interaction, Russian formalist literary theory, linguistic pragmatics, sociolinguistics, early anthropological linguistics and structuralist grammatical theory, together with his own theoretical contributions, yielding a comprehensive account of the semiotics of human communication and its relation to culture. His main influence was Charles Sanders Peirce, Ferdinand de Saussure, and Roman Jakobson.

Current applications

Some applications of semiotics include:

• Representation of a methodology for the analysis of "texts" regardless of the medium in which it is presented. For these purposes, "text" is any message preserved in a form whose existence is independent of both sender and receiver;
• By scholars and professional researchers as a method to interpret meanings behind symbols and how the meanings are created;
• Potential improvement of ergonomic design in situations where it is important to ensure that human beings are able to interact more effectively with their environments, whether it be on a large scale, as in architecture, or on a small scale, such as the configuration of instrumentation for human use; and
• Marketing: Epure, Eisenstat, and Dinu (2014) express that "semiotics allows for the practical distinction of persuasion from manipulation in marketing communication." Semiotics are used in marketing as a persuasive device to influence buyers to change their attitudes and behaviors in the market place. There are two ways that Epure, Eisenstat, and Dinu (2014), building on the works of Roland Barthes, state in which semiotics are used in marketing: Surface: signs are used to create personality for the product, creativity plays its foremost role at this level; Underlying: the concealed meaning of the text, imagery, sounds, etc.

In some countries, the role of semiotics is limited to literary criticism and an appreciation of audio and visual media. This narrow focus may inhibit a more general study of the social and political forces shaping how different media are used and their dynamic status within modern culture. Issues of technological determinism in the choice of media and the design of communication strategies assume new importance in this age of mass media.

Main institutions

A world organization of semioticians, the International Association for Semiotic Studies, and its journal Semiotica, was established in 1969. The larger research centers together with teaching program include the semiotics departments at the University of Tartu, University of Limoges, Aarhus University, and Bologna University.

Publications

Publication of research is both in dedicated journals such as Sign Systems Studies, established by Juri Lotman and published by Tartu University Press; Semiotica, founded by Thomas A. Sebeok and published by Mouton de Gruyter; Zeitschrift für Semiotik; European Journal of Semiotics; Versus (founded and directed by Umberto Eco), The American Journal of Semiotics, et al.; and as articles accepted in periodicals of other disciplines, especially journals oriented toward philosophy and cultural criticism, communication theory, etc.

The major semiotic book series Semiotics, Communication, Cognition, published by De Gruyter Mouton (series editors Paul Cobley and Kalevi Kull) replaces the former "Approaches to Semiotics" (series editor Thomas A. Sebeok, 127 volumes) and "Approaches to Applied Semiotics" (7 volumes). Since 1980 the Semiotic Society of America has produced an annual conference series: Semiotics: The Proceedings of the Semiotic Society of America.