Cognitive development

From Wikipedia, the free encyclopedia

 

Cognitive development is a field of study in neuroscience and psychology focusing on a child's development in terms of information processing, conceptual resources, perceptual skill, language learning, and other aspects of the developed adult brain and cognitive psychology. Qualitative differences between how a child processes their waking experience and how an adult processes their waking experience are acknowledged (Such as object permanence, the understanding of logical relations, and cause-effect reasoning in school age children). Cognitive development is defined in adult terms as the emergence of ability to consciously cognize and consciously understand and articulate their understanding. From an adult point of view, cognitive development can also be called intellectual development. Cognitive development is how a person perceives, thinks, and gains understanding of their world through the relations of genetic and learning factors. There are four stages to Cognitive Development information development, reasoning, intelligence, language, and memory. These stages start when the baby is about 18 months old, they play with toys, listen to their parents speak, they watch tv, anything that catches their attention helps build their Cognitive Development.

Jean Piaget was a major force establishing this field, forming his "theory of cognitive development". Piaget proposed four stages of cognitive development: the sensorimotor, preoperational, concrete operational and formal operational period. Many of Piaget's theoretical claims have since fallen out of favor. Still, his description of the most prominent changes in cognition with age, is generally still accepted today (e.g., how early perception moves from being dependent on concrete, external actions. Later, abstract understanding of observable aspects of reality can be captured; leading to, discovery of underlying abstract rules and principles, usually starting in adolescence)

In recent years, however, alternative models have been advanced, including information-processing theory, neo-Piagetian theories of cognitive development, which aim to integrate Piaget's ideas with more recent models and concepts in developmental and cognitive science, theoretical cognitive neuroscience, and social-constructivist approaches. A major controversy in cognitive development has been "nature versus nurture", that is, the question if cognitive development is mainly determined by an individual's innate qualities ("nature"), or by their personal experiences ("nurture"). However, it is now recognized by most experts that this is a false dichotomy: there is overwhelming evidence from biological and behavioral sciences that from the earliest points in development, gene activity interacts with events and experiences in the environment.

Historical origins: The history and theory of cognitive development

Jean Piaget is inexorably linked to cognitive development. It is clear in Piaget's writings that there are influences from many historical predecessors. A few that are worth mentioning are included in the following Historical Origins chart. It is intended to be a more inclusive list of researchers who have studied the processes of acquiring more complex ways of thinking as people grow and develop: 

	DOB/death	Contribution to cognitive development
Jean-Jacques Rousseau	1712–1778	Wrote Emile, or On Education (1762). He discusses childhood development as happening in three stages. First stage, up to age 12, the child is guided by their emotions and impulses. The second stage, ages 12–16, the child's reason starts to develop. In the third and final stage, age 16 and up, the child develops into an adult.
James Sully	1842–1923	Wrote several books on childhood development, including Studies of Childhood (1895) and Children's Ways[6] (1897). He used a detailed observational study method with the children. Contemporary research in child development actually repeats observations, and observational methods, summarized by Sully in Studies of Childhood, such as the mirror technique.
Lev Vygotsky	1896–1934	Area of specialty was developmental psychology. Main contribution is the somewhat controversial "zone of proximal development" (ZPD) which states that play should be children's main activity as this is their main source of development in terms of emotional, volitional, and cognitive development. ZPD is the link between children's learning and cognitive development.
Maria Montessori	1870–1952	She began her career working with mentally disabled children in 1897, then conducted observation and experimental research in elementary schools. Wrote The Discovery of the Child (1948). Discussed the Four Planes of Development: birth–6, 6–12, 12–18, and 18–24. The Montessori Method now has three developmentally-meaningful age groups: 2–2.5, 2.5–6, and 6–12. She was working on human behavior in older children but only published lecture notes on the subject.
Jean Piaget	1896–1980	Piaget was the first psychologist and philosopher to brand this type of study as "cognitive development". Other researchers, in multiple disciplines, had studied development in children before, but Piaget is often credited as being the first one to make a systematic study of cognitive development and gave it its name. His main contribution is the stage theory of child cognitive development. He also published his observational studies of cognition in children, and created a series of simple tests to reveal different cognitive abilities in children.
Lawrence Kohlberg	1927–1987	Wrote the theory of stages of moral development, which extended Piaget's findings of cognitive development and showed that they continue through the lifespan. Kohlberg's six stages follow Piaget's constructivist requirements in that stages can not be skipped and it is very rare to regress in stages. Notable works: Moral Stages and Moralization: The Cognitive-Development Approach[8] (1976) and Essays on Moral Development (1981)

Piaget's theory of cognitive development

Jean Piaget (1896–1980) believed that people move through stages of development that allow them to think in new, more complex ways.

Sensorimotor stage

The first stage in Piaget's stages of cognitive development is the sensorimotor stage. This stage lasts from birth to two years old. During this stage, behaviors lack a sense of thought and logic. Behaviors gradually move from acting upon inherited reflexes to interacting with the environment with a goal in mind and being able to represent the external world at the end.

The sensorimotor stage has been broken down into six sub stages that explain the gradual development of infants from birth to age 2. Once the child gains the ability to mentally represent reality, the child begins the transition to the preoperational stage of development.

Birth to one month

Each child is born with inherited reflexes that they use to gain knowledge and understanding about their environment. Examples of these reflexes include grasping and sucking.

1–4 months

Children repeat behaviors that happen unexpectedly because of their reflexes. For example, a child's finger comes in contact with the mouth and the child starts sucking on it. If the sensation is pleasurable to the child, then the child will attempt to recreate the behavior. Infants use their initial reflexes (grasping and sucking) to explore their environment and create schemes. Schemes are groups of similar actions or thoughts that are used repeatedly in response to the environment. Once a child begins to create schemes they use accommodation and assimilation to become progressively adapted to the world. Assimilation is when a child responds to a new event in a way that is consistent with an existing schema. For example, an infant may assimilate a new teddy bear into their putting things in their mouth scheme and use their reflexes to make the teddy bear go into their mouth. Accommodation is when a child either modifies an existing scheme or forms an entirely new schema to deal with a new object or event. For example, an infant may have to open his or her mouth wider than usual to accommodate the teddy bear's paw.

5–8 months

Child has an experience with an external stimulus that they find pleasurable, so they try to recreate that experience. For example, a child accidentally hits the mobile above the crib and likes to watch it spin. When it stops the child begins to grab at the object to make it spin again. In this stage, habits are formed from general schemes that the infant has created but there is not yet, from the child's point of view, any differentiation between means and ends. Children cannot also focus on multiple tasks at once, and only focus on the task at hand. The child may create a habit of spinning the mobile in its crib, but they are still trying to find out methods to reach the mobile in order to get it to spin in the way that they find pleasurable. Once there is another distraction (say the parent walks in the room) the baby will no longer focus on the mobile. Toys should be given to infants that respond to a child's actions to help foster their investigative instincts. For example, a toy plays a song when you push one button, and then a picture pops up if you push another button.

8–12 months

Behaviors will be displayed for a reason rather than by chance. They begin to understand that one action can cause a reaction. They also begin to understand object permanence, which is the realization that objects continue to exist when removed from view. For example: The baby wants a rattle but the blanket is in the way. The baby moves the blanket to get the rattle. Now that the infant can understand that the object still exists, they can differentiate between the object, and the experience of the object. According to psychologist David Elkind, "An internal representation of the absent object is the earliest manifestation of the symbolic function which develops gradually during the second year of life whose activities dominate the next stage of mental growth."

12–18 months

Actions occur deliberately with some variation. For example, a baby drums on a pot with a wooden spoon, then drums on the floor, then on the table.

18–24 months

Children begin to build mental symbols and start to participate in pretend play. For example, a child is mixing ingredients together but doesn't have a spoon so they pretend to use one or use another object to replace the spoon. Symbolic thought is a representation of objects and events as mental entities or symbols which helps foster cognitive development and the formation of imagination. According to Piaget, the infant begins to act upon intelligence rather than habit at this point. The end product is established after the infant has pursued for the appropriate means. The means are formed from the schemes that are known by the child. The child is starting to learn how to use what it has learned in the first two years to develop and further explore their environment.

Preoperational stage

Lasts from 2 years of age until 6 or 7. It can be characterized in two somewhat different ways. In his early work, before he had developed his structuralist theory of cognition, Piaget described the child's thoughts during this period as being governed by principles such as egocentrism, animism and other similar constructs. Egocentrism is when a child can only see a certain situation his or her own way. One cannot comprehend that other people have other views and perceptions of scenarios. Animism is when an individual gives a lifeless object human-like qualities. An individual usually believes that this object has human emotions, thoughts and intentions. Once he had proposed his structuralist theory, Piaget characterized the preoperational child as lacking the cognitive structures possessed by the concrete operational child. The absence of these structures explains, in part, the behaviors Piaget had previously described as egocentric and animistic, for example, an inability to comprehend that another individual may have different emotional responses to similar experiences. During this stage children also become increasingly adept at using symbols as evidenced by the increase in playing and pretending.

Concrete operational stage

Lasts from 6 or 7 years until about 12 or 13. During this stage, the child's cognitive structures can be characterized by reality. Piaget argues that the same general principles can be discerned in a wide range of behaviors. One of the best-known achievements of this stage is conservation. In a typical conservation experiment a child is asked to judge whether or not two quantities are the same – such as two equal quantities of liquid in a short and tall glass. A preoperational child will typically judge the taller, thinner glass to contain more, while a concrete operational child will judge the amounts still to be the same. The ability to reason in this way reflects the development of a principle of conservation.

Formal operational stage

This stage lasts from 12 or 13 until adulthood, when people are advancing from logical reasoning with concrete examples to abstract examples. The need for concrete examples is no longer necessary because abstract thinking can be used instead. In this stage adolescents are also able to view themselves in the future and can picture the ideal life they would like to pursue. Some theorists believe the formal operational stage can be divided into two sub-categories: early formal operational and late formal operation thought. Early formal operational thoughts may be just fantasies, but as adolescents advance to late formal operational thought the life experiences they have encountered changes those fantasy thoughts to realistic thoughts.

Criticism

Many of Piaget's claims have fallen out of favor. For example, he claimed that young children cannot conserve numbers. However, further experiments showed that children did not really understand what was being asked of them. When the experiment is done with candies, and the children are asked which set they want rather than having to tell an adult which is more, they show no confusion about which group has more items.

Piaget's theory of cognitive development ends at the formal operational stage that is usually developed in early adulthood. It does not take into account later stages of adult cognitive development as described by, for example, Harvard University professor Robert Kegan.

Other theoretical perspectives on cognitive development

Lev Vygotsky's theory

Lev Vygotsky's (1896-1934) theory is based on social learning as the most important aspect of cognitive development. In Vygotsky's theory, adults are very important for young children's development. They help children learn through mediation, which is modeling and explaining concepts. Together, adults and children master concepts of their culture and activities. Vygotsky believed we get our complex mental activities through social learning. A significant part of Vygotsky's theory is based on the zone of proximal development, which he believes is when the most effective learning takes place. The Zone of proximal development is what a child cannot accomplish alone but can accomplish with the help of an MKO (more knowledgeable other). Vygotsky also believed culture is a very important part of cognitive development such as the language, writing and counting system used in that culture. Another aspect of Vygotsky’ theory is private speech. Private speech is when a person talks to themselves in order to help themselves problem solve. Scaffolding or providing support to a child and then slowly removing support and allowing the child to do more on their own over time is also an aspect of Vygotsky’s theory.

Speculated core systems of cognition

Empiricists study how these skills may be learned in such a short time. The debate is over whether these systems are learned by general-purpose learning devices, or domain-specific cognition. Moreover, many modern cognitive developmental psychologists, recognizing that the term "innate" does not square with modern knowledge about epigenesis, neurobiological development, or learning, favor a non-nativist framework. Researchers who discuss "core systems" often speculate about differences in thinking and learning between proposed domains.

Researchers who posit a set of so-called "core domains" suggest that children have an innate sensitivity to specific kinds of patterns of information. Those commonly cited include:

Number

Infants appear to have two systems for dealing with numbers. One deals with small numbers, often called subitizing. Another deals with larger numbers in an approximate fashion.

Space

Very young children appear to have some skill in navigation. This basic ability to infer the direction and distance of unseen locations develops in ways that are not entirely clear. However, there is some evidence that it involves the development of complex language skills between 3 and 5 years. Also, there is evidence that this skill depends importantly on visual experience, because congenitally blind individuals have been found to have impaired abilities to infer new paths between familiar locations.

Visual perception

One of the original nativist versus empiricist debates was over depth perception. There is some evidence that children less than 72 hours old can perceive such complex things as biological motion. However, it is unclear how visual experience in the first few days contributes to this perception. There are far more elaborate aspects of visual perception that develop during infancy and beyond.

Essentialism

Young children seem to be predisposed to think of biological entities (e.g., animals and plants) in an essentialistic way. This means that they expect such entities (as opposed to, e.g., artifacts) to have many traits such as internal properties that are caused by some "essence" (such as, in our modern Western conceptual framework, the genome).

Language acquisition

A major, well-studied process and consequence of cognitive development is language acquisition. The traditional view was that this is the result of deterministic, human-specific genetic structures and processes. Other traditions, however, have emphasized the role of social experience in language learning. However, the relation of gene activity, experience, and language development is now recognized as incredibly complex and difficult to specify. Language development is sometimes separated into learning of phonology (systematic organization of sounds), morphology (structure of linguistic units—root words, affixes, parts of speech, intonation, etc.), syntax (rules of grammar within sentence structure), semantics (study of meaning), and discourse or pragmatics (relation between sentences). However, all of these aspects of language knowledge—which were originally posited by the linguist Noam Chomsky to be autonomous or separate—are now recognized to interact in complex ways.

Bilingualism

It wasn’t until recently that bilingualism had been accepted as a contributing factor to cognitive development. There have been a number of studies showing how bilingualism contributes to the executive function of the brain, which is the main center at which cognitive development happens. According to Bialystok in “Bilingualism and the Development of Executive Function: The Role of Attention”, children who are bilingual, have to actively filter through the two different languages to select the one they need to use, which in turn makes the development stronger in that center.

Whorf's hypothesis

Benjamin Whorf (1897–1941), while working as a student of Edward Sapir, posited that a person's thinking depends on the structure and content of their social group's language. In other words, it is the belief that language determines our thoughts and perceptions. For example, it used to be thought that the Greeks, who wrote left to right, thought differently than Egyptians since the Egyptians wrote right to left. Whorf's theory was so strict that he believed if a word is absent in a language, then the individual is unaware of the object's existence. This theory was played out in George Orwell's book, Animal Farm; the pig leaders slowly eliminated words from the citizen's vocabulary so that they were incapable of realizing what they were missing. The Whorfian hypothesis failed to recognize that people can still be aware of the concept or item, even though they lack efficient coding to quickly identify the target information.

Quine's bootstrapping hypothesis

Willard Van Orman Quine (1908–2000) argued that there are innate conceptual biases that enable the acquisition of language, concepts, and beliefs. Quine's theory follows nativist philosophical traditions, such as the European rationalist philosophers, for example Immanuel Kant.

Neo-Piagetian theories of cognitive development

Neo-Piagetian theories of cognitive development emphasized the role of information processing mechanisms in cognitive development, such as attention control and working memory. They suggested that progression along Piagetian stages or other levels of cognitive development is a function of strengthening of control mechanisms and enhancement of working memory storage capacity.

Lev Vygotsky vs. Jean Piaget

Unlike Jean Piaget, who believed development comes before learning, Vygotsky believed that learning comes before development and that one must learn first to be able to develop into a functioning human being. Vygotsky's theory is different from Piaget's theory of cognitive development in four ways. 1. Vygotsky believes culture affects cognitive development more. Piaget thinks that cognitive development is the same across the world, while Vygotsky has the idea that culture makes cognitive development different. 2. Social factors heavily influence cognitive development under Vygotsky's beliefs. Environment and parents the child has will play a big role in a child's cognitive development. The child learns through the Zone of Proximal Development with help from their parent. 3. Vygotsky believes that language is important in cognitive development. While Piaget considers thought as an important role, Vygotsky sees thought and language as different, but eventually coming together. Vygotsky emphasizes the role of inner speech being the first thing to cause cognitive development to form. 4. Cognitive development is strongly influenced by adults. Children observe adults in their life and gain knowledge about their specific culture based on things the adults around them do. They do this through mediation and scaffolding.

Neuroscience

During development, especially the first few years of life, children show interesting patterns of neural development and a high degree of neuroplasticity. Neuroplasticity, as explained by the World Health Organization, can be summed up in three points. 1.) Any adaptive mechanism used by the nervous system to repair itself after injury. 2.) Any means by which the nervous system can repair individually damaged central circuits. 3.) Any means by which the capacity of the central nervous system can adapt to new physiological conditions and environment. The relation of brain development and cognitive development is extremely complex and, since the 1990s, has been a growing area of research. 

Cognitive development and motor development may also be closely interrelated. When a person experiences a neurodevelopmental disorder and their cognitive development is disturbed, we often see adverse effects in motor development as well. Cerebellum, which is the part of brain that is most responsible for motor skills, has been shown to have significant importance in cognitive functions in the same way that prefrontal cortex has important duties in not only cognitive abilities but also development of motor skills. To support this, there is evidence of close co-activation of neocerebellum and dorsolateral prefrontal cortex in functional neuroimaging as well as abnormalities seen in both cerebellum and prefrontal cortex in the same developmental disorder. In this way, we see close interrelation of motor development and cognitive development and they cannot operate in their full capacity when either of them are impaired or delayed.

Cultural influences

From cultural psychologists' view, minds and culture shape each other. In other words, culture can influence brain structures which then influence our interpretation of the culture. These examples reveal cultural variations in neural responses:

Figure-line task (Hedden et al., 2008)

Behavioral research has shown that one's strength in independent or interdependent tasks differ based on their cultural context. In general, East Asian cultures are more interdependent whereas Western cultures are more independent. Hedden et al. assessed functional magnetic resonance imaging (fMRI) responses of East Asians and Americans while they performed independent (absolute) or interdependent (relative) tasks. The study showed that participants used regions of the brain associated with attentional control when they had to perform culturally incongruent tasks. In other words, neural paths used for the same task were different for Americans and East Asians (Hedden et al., 2008).

Transcultural neuroimaging studies (Han s. and Northoff G., 2008)

New studies in transcultural neuroimaging studies have demonstrated that one’s cultural background can influence the neural activity that underlies both high (for example, social cognition) and low (for example, perception) level cognitive functions. Studies demonstrated that groups that come from different cultures or that have been exposed to culturally different stimuli have differences in neural activity. For example, differences were found in that of the pre motor cortex during mental calculation and that of the VMPFC during trait judgements of one’s mother from people with different cultural backgrounds. In conclusion, since differences were found in both high-level and low-level cognition one can assume that our brain’s activity is strongly and, at least in part, constitutionally shaped by its sociocultural context (Han s. and Northoff G., 2008).

Kobayashi et al., 2007

Kobayashi et al. compared American-English monolingual and Japanese-English bilingual children's brain responses in understanding others' intentions through false-belief story and cartoon tasks. They found universal activation of the region bilateral ventromedial prefrontal cortex in theory of mind tasks. However, American children showed greater activity in the left inferior frontal gyrus during the tasks whereas Japanese children had greater activity in the right inferior frontal gyrus during the Japanese Theory of Mind tasks. In conclusion, these examples suggest that the brain's neural activities are not universal but are culture dependent.

Recapitulation theory

From Wikipedia, the free encyclopedia

 

The theory of recapitulation, also called the biogenetic law or embryological parallelism—often expressed using Ernst Haeckel's phrase "ontogeny recapitulates phylogeny"—is a historical hypothesis that the development of the embryo of an animal, from fertilization to gestation or hatching (ontogeny), goes through stages resembling or representing successive adult stages in the evolution of the animal's remote ancestors (phylogeny). It was formulated in the 1820s by Étienne Serres based on the work of Johann Friedrich Meckel, after whom it is also known as Meckel–Serres law.

Since embryos also evolve in different ways, the shortcomings of the theory had been recognized by the early 20th century, and it had been relegated to "biological mythology" by the mid-20th century.

Analogies to recapitulation theory have been formulated in other fields, including cognitive development and art criticism.

Embryology

Meckel, Serres, Geoffroy

The idea of recapitulation was first formulated in biology from the 1790s onwards by the German natural philosophers Johann Friedrich Meckel and Carl Friedrich Kielmeyer, and by Étienne Serres after which, Marcel Danesi states, it soon gained the status of a supposed biogenetic law.

The embryological theory was formalised by Serres in 1824–26, based on Meckel's work, in what became known as the "Meckel-Serres Law". This attempted to link comparative embryology with a "pattern of unification" in the organic world. It was supported by Étienne Geoffroy Saint-Hilaire, and became a prominent part of his ideas. It suggested that past transformations of life could have been through environmental causes working on the embryo, rather than on the adult as in Lamarckism. These naturalistic ideas led to disagreements with Georges Cuvier. The theory was widely supported in the Edinburgh and London schools of higher anatomy around 1830, notably by Robert Edmond Grant, but was opposed by Karl Ernst von Baer's ideas of divergence, and attacked by Richard Owen in the 1830s.

George Romanes's 1892 copy of Ernst Haeckel's controversial embryo drawings

Haeckel

Ernst Haeckel (1834–1919) attempted to synthesize the ideas of Lamarckism and Goethe's Naturphilosophie with Charles Darwin's concepts. While often seen as rejecting Darwin's theory of branching evolution for a more linear Lamarckian view of progressive evolution, this is not accurate: Haeckel used the Lamarckian picture to describe the ontogenetic and phylogenetic history of individual species, but agreed with Darwin about the branching of all species from one, or a few, original ancestors. Since early in the twentieth century, Haeckel's "biogenetic law" has been refuted on many fronts.

Haeckel formulated his theory as "Ontogeny recapitulates phylogeny". The notion later became simply known as the recapitulation theory. Ontogeny is the growth (size change) and development (structure change) of an individual organism; phylogeny is the evolutionary history of a species. Haeckel claimed that the development of advanced species passes through stages represented by adult organisms of more primitive species. Otherwise put, each successive stage in the development of an individual represents one of the adult forms that appeared in its evolutionary history.

For example, Haeckel proposed that the pharyngeal grooves between the pharyngeal arches in the neck of the human embryo not only roughly resembled gill slits of fish, but directly represented an adult "fishlike" developmental stage, signifying a fishlike ancestor. Embryonic pharyngeal slits, which form in many animals when the thin branchial plates separating pharyngeal pouches and pharyngeal grooves perforate, open the pharynx to the outside. Pharyngeal arches appear in all tetrapod embryos: in mammals, the first pharyngeal arch develops into the lower jaw (Meckel's cartilage), the malleus and the stapes.

Haeckel produced several embryo drawings that often overemphasized similarities between embryos of related species. Modern biology rejects the literal and universal form of Haeckel's theory, such as its possible application to behavioural ontogeny, i.e. the psychomotor development of young animals and human children.

Contemporary criticism

Drawing by Wilhelm His of chick brain compared to folded rubber tube, 1874. Ag (Anlage) = Optic lobes, matching bulges in rubber tube.

 

Haeckel's drawings misrepresented observed human embryonic development to such an extent that he attracted the opposition of several members of the scientific community, including the anatomist Wilhelm His, who had developed a rival "causal-mechanical theory" of human embryonic development. His's work specifically criticised Haeckel's methodology, arguing that the shapes of embryos were caused most immediately by mechanical pressures resulting from local differences in growth. These differences were, in turn, caused by "heredity". His compared the shapes of embryonic structures to those of rubber tubes that could be slit and bent, illustrating these comparisons with accurate drawings. Stephen Jay Gould noted in his 1977 book Ontogeny and Phylogeny that His's attack on Haeckel's recapitulation theory was far more fundamental than that of any empirical critic, as it effectively stated that Haeckel's "biogenetic law" was irrelevant.

Embryology theories of Ernst Haeckel and Karl Ernst von Baer compared

 

Darwin proposed that embryos resembled each other since they shared a common ancestor, which presumably had a similar embryo, but that development did not necessarily recapitulate phylogeny: he saw no reason to suppose that an embryo at any stage resembled an adult of any ancestor. Darwin supposed further that embryos were subject to less intense selection pressure than adults, and had therefore changed less.

Modern status

Modern evolutionary developmental biology (evo-devo) follows von Baer, rather than Darwin, in pointing to active evolution of embryonic development as a significant means of changing the morphology of adult bodies. Two of the key principles of evo-devo, namely that changes in the timing (heterochrony) and positioning (heterotopy) within the body of aspects of embryonic development would change the shape of a descendant's body compared to an ancestor's, were however first formulated by Haeckel in the 1870s. These elements of his thinking about development have thus survived, whereas his theory of recapitulation has not.

The Haeckelian form of recapitulation theory is considered defunct. Embryos do undergo a period where their morphology is strongly shaped by their phylogenetic position, rather than selective pressures, but that means only that they resemble other embryos at that stage, not ancestral adults as Haeckel had claimed. The modern view is summarised by the University of California Museum of Paleontology:

Embryos do reflect the course of evolution, but that course is far more intricate and quirky than Haeckel claimed. Different parts of the same embryo can even evolve in different directions. As a result, the Biogenetic Law was abandoned, and its fall freed scientists to appreciate the full range of embryonic changes that evolution can produce—an appreciation that has yielded spectacular results in recent years as scientists have discovered some of the specific genes that control development.

Applications to other areas

The idea that ontogeny recapitulates phylogeny has been applied to some other areas.

Cognitive development

English philosopher Herbert Spencer was one of the most energetic proponents of evolutionary ideas to explain many phenomena. In 1861, five years before Haeckel first published on the subject, Spencer proposed a possible basis for a cultural recapitulation theory of education with the following claim:

If there be an order in which the human race has mastered its various kinds of knowledge, there will arise in every child an aptitude to acquire these kinds of knowledge in the same order... Education is a repetition of civilization in little.

— Herbert Spencer

G. Stanley Hall used Haeckel's theories as the basis for his theories of child development. His most influential work, "Adolescence: Its Psychology and Its Relations to Physiology, Anthropology, Sociology, Sex, Crime, Religion and Education" in 1904 suggested that each individual's life course recapitulated humanity's evolution from "savagery" to "civilization". Though he has influenced later childhood development theories, Hall's conception is now generally considered racist. Developmental psychologist Jean Piaget favored a weaker version of the formula, according to which ontogeny parallels phylogeny because the two are subject to similar external constraints.

The Austrian pioneer of psychoanalysis, Sigmund Freud, also favored Haeckel's doctrine. He was trained as a biologist under the influence of recapitulation theory during its heyday, and retained a Lamarckian outlook with justification from the recapitulation theory. Freud also distinguished between physical and mental recapitulation, in which the differences would become an essential argument for his theory of neuroses.

In the late 20th century, studies of symbolism and learning in the field of cultural anthropology suggested that "both biological evolution and the stages in the child's cognitive development follow much the same progression of evolutionary stages as that suggested in the archaeological record".

Art criticism

The musicologist Richard Taruskin in 2005 applied the phrase "ontogeny becomes phylogeny" to the process of creating and recasting art history, often to assert a perspective or argument. For example, the peculiar development of the works by modernist composer Arnold Schoenberg (here an "ontogeny") is generalized in many histories into a "phylogeny" – a historical development ("evolution") of Western music toward atonal styles of which Schoenberg is a representative. Such historiographies of the "collapse of traditional tonality" are faulted by art historians as asserting a rhetorical rather than historical point about tonality's "collapse".

Taruskin also developed a variation of the motto into the pun "ontogeny recapitulates ontology" to refute the concept of "absolute music" advancing the socio-artistic theories of the musicologist Carl Dahlhaus. Ontology is the investigation of what exactly something is, and Taruskin asserts that an art object becomes that which society and succeeding generations made of it. For example, Johann Sebastian Bach's St. John Passion, composed in the 1720s, was appropriated by the Nazi regime in the 1930s for propaganda. Taruskin claims the historical development of the St John Passion (its ontogeny) as a work with an anti-Semitic message does, in fact, inform the work's identity (its ontology), even though that was an unlikely concern of the composer. Music or even an abstract visual artwork can not be truly autonomous ("absolute") because it is defined by its historical and social reception.

Craniometry

From Wikipedia, the free encyclopedia

 

A human skull and measurement device from 1902.

 

Craniometry is measurement of the cranium (the main part of the skull), usually the human cranium. It is a subset of cephalometry, measurement of the head, which in humans is a subset of anthropometry, measurement of the human body. It is distinct from phrenology, the pseudoscience that tried to link personality and character to head shape, and physiognomy, which tried the same for facial features. However, these fields have all claimed the ability to predict traits or intelligence. 

They were once intensively practised in anthropology, in particular in physical anthropology in the 19th and the first part of the 20th century. Theories attempting to scientifically justify the segregation of society based on race became popular at this time, one of their prominent figures being Georges Vacher de Lapouge (1854–1936), who divided humanity into various, hierarchized, different "races", spanning from the "Aryan white race, dolichocephalic" (from the Ancient Greek kephalê, head, and dolikhos, long and thin), to the "brachycephalic" (short and broad-headed) race. On the other hand, craniometry was also used as evidence against the existence of a "Nordic race" and also by Franz Boas who used the cephalic index to show the influence of environmental factors. Charles Darwin used craniometry and the study of skeletons to demonstrate his theory of evolution first expressed in On the Origin of Species (1859).

More direct measurements involve examinations of brains from corpses, or more recently, imaging techniques such as MRI, which can be used on living persons. Such measurements are used in research on neuroscience and intelligence.

The cephalic index

Swedish professor of anatomy Anders Retzius (1796–1860) first used the cephalic index in physical anthropology to classify ancient human remains found in Europe. He classified brains into three main categories, "dolichocephalic" (from the Ancient Greek kephalê, head, and dolikhos, long and thin), "brachycephalic" (short and broad) and "mesocephalic" (intermediate length and width). 

These terms were then used by Georges Vacher de Lapouge (1854–1936), one of the pioneers of scientific theories in this area and a theoretician of eugenics, who in L'Aryen et son rôle social (1899 – "The Aryan and his social role") divided humanity into various, hierarchized, different "races", spanning from the "Aryan white race, dolichocephalic", to the "brachycephalic" "mediocre and inert" race, best represented by the "Jew [sic]."

Between these, Vacher de Lapouge identified the "Homo europaeus (Teutonic, Protestant, etc.), the "Homo alpinus" (Auvergnat, Turkish, etc.), and finally the "Homo mediterraneus" (Napolitano, Andalus, etc.). "Homo africanus" (Congo, Florida) was even excluded from the discussion. Vacher de Lapouge became one of the leading inspirations of Nazi anti-semitism and Nazi ideology. His classification was mirrored in William Z. Ripley in The Races of Europe (1899).

Craniometry and anthropology

Pithecometra: In the frontispiece from his 1863 Evidence as to Man's Place in Nature, Thomas Huxley compared skeletons of apes to humans.

In 1784, Louis-Jean-Marie Daubenton, who wrote many comparative anatomy memoirs for the Académie française, published the Mémoire sur les différences de la situation du grand trou occipital dans l’homme et dans les animaux (which translates as Memoir on the Different Positions of the Occipital Foramen in Man and Animals).

Six years later, Pieter Camper (1722–1789), distinguished both as an artist and as an anatomist, published some lectures containing an account of his craniometrical methods. These laid the foundation of all subsequent work.

Pieter Camper invented the "facial angle", a measure meant to determine intelligence among various species. According to this technique, a "facial angle" was formed by drawing two lines: one horizontally from the nostril to the ear; and the other perpendicularly from the advancing part of the upper jawbone to the most prominent part of the forehead. 

Camper claimed that antique statues presented an angle of 90°, Europeans of 80°, Black people of 70° and the orangutan of 58°, thus displaying a hierarchic view of mankind, based on a decadent conception of history. This scientific research was continued by Étienne Geoffroy Saint-Hilaire (1772–1844) and Paul Broca (1824–1880).

In 1856, workers found in a limestone quarry the skull of a Neanderthal man, thinking it to be the remains of a bear. They gave the material to amateur naturalist Johann Karl Fuhlrott, who turned the fossils over to anatomist Hermann Schaaffhausen. The discovery was jointly announced in 1857, giving rise to paleoanthropology.

Measurements were first made to compare the skulls of men with those of other animals. This wide comparison constituted the first subdivision of craniometric studies. The artist-anatomist Camper's developed a theory to measure the facial angle, for which he is chiefly known in later anthropological literature.

Camper's work followed 18th-century scientific theories. His measurements of facial angle were used to liken the skulls of non-Europeans to those of apes. 

Selection of Primate skulls.

 

"Craniometry" also played a role in the foundation of the United States and the ideologies or racism that would become ingrained in the American psyche. As John Jeffries articulates in The Collision of Culture the Anglo-Saxon hegemony present in America during the eighteenth and nineteenth century helped establish "The American School of Craniometry" which helped establish the American and Western concept of race. As Jeffries points out the rigid establishment of race in eighteenth-century American society came from a new school of sciences which sought to distance Anglo-Saxons from the African American population. The distancing of the African population in American society through craniometry helped greatly in the efforts to scientifically prove they were inferior. The ideologies set forth by this new "American School" of thought were then used to justify maintaining an enslaved population to sustain the increasing number of slave plantations in the American South during the eighteenth and nineteenth centuries.

In the 19th century the names of notable contributors to the literature of craniometry quickly increased in number. While it is impossible to analyse each contribution, or even record a complete list of the names of the authors, notable researchers who used craniometric methods to compare humans to other animals included Paul Broca (1824–1880), founder of the Anthropological Society in 1859 in France; and T. H. Huxley (1825–1895) of England.

By comparing skeletons of apes to man, Huxley backed up Charles Darwin's theory of evolution and developed the "Pithecometra principle", which stated that man and ape were descended from a common ancestor.

Ernst Haeckel (1834–1919) became famous for his now outdated "recapitulation theory", according to which each individual mirrored the evolution of the whole species during his life. Although outdated, his work contributed then to the examination of human life.

These researches on skulls and skeletons helped liberate 19th-century European science from its ethnocentric biases. In particular, Eugène Dubois' (1858–1940) discovery in 1891 in Indonesia of the "Java Man", the first specimen of Homo erectus to be discovered, demonstrated mankind's deep ancestry outside Europe.

Cranial capacity, races and 19th–20th-century scientific ideas

Samuel George Morton (1799–1851), one of the inspirers of physical anthropology, collected hundreds of human skulls from all over the world and started trying to find a way to classify them according to some logical criterion. Influenced by the common theories of his time, he claimed that he could judge the intellectual capacity of a race by the cranial capacity (the measure of the volume of the interior of the skull).

After inspecting three mummies from ancient Egyptian catacombs, Morton concluded that Caucasians and other races were already distinct three thousand years ago. Since the bible indicated that Noah's Ark had washed up on Mount Ararat, only a thousand years ago before this, Morton claimed that Noah's sons could not possibly account for every race on earth. According to Mortons theory of polygenism, races have been separate since the start.

Morton claimed that he could judge the intellectual capacity of a race by the skull size. A large skull meant a large brain and high intellectual capacity, and a small skull indicated a small brain and decreased intellectual capacity. Morton collected hundreds of human skulls from all over the world. By studying these skulls he claimed that each race had a separate origin. Morton had many skulls from ancient Egypt, and concluded that the ancient Egyptians were not African, but were White. His two major monographs were the Crania Americana (1839), An Inquiry into the Distinctive Characteristics of the Aboriginal Race of America and Crania Aegyptiaca (1844). 

Based on craniometry data, Morton claimed in Crania Americana that the Caucasians had the biggest brains, averaging 87 cubic inches, Indians were in the middle with an average of 82 cubic inches and Negroes had the smallest brains with an average of 78 cubic inches.

Stephen Jay Gould (1941–2002), an American paleontologist, evolutionary biologist and historian of science, studied these craniometric works in The Mismeasure of Man (1981) and claimed Samuel Morton had fudged data and "overpacked" the skulls with filler in order to justify his preconceived notions on racial differences. A subsequent study by the anthropologist John Michael found Morton's original data to be more accurate than Gould describes, concluding that "[c]ontrary to Gould's interpretation... Morton's research was conducted with integrity."

In 2011, physical anthropologists at the University of Pennsylvania, which owns Morton's collection, published a study that concluded that almost every detail of Gould's analysis was wrong and that "Morton did not manipulate his data to support his preconceptions, contra Gould." They identified and remeasured half of the skulls used in Morton's reports, finding that in only 2% of cases did Morton's measurements differ significantly from their own and that these errors either were random or gave a larger than accurate volume to African skulls, the reverse of the bias that Gould imputed to Morton.

Morton's followers, particularly Josiah C. Nott and George Gliddon in their monumental tribute to Morton's work, Types of Mankind (1854), carried Morton's ideas further and backed up his findings which supported the notion of polygenism.

Charles Darwin opposed Nott and Glidon in his 1871 The Descent of Man, arguing for a monogenism of the species. Darwin conceived the common origin of all humans (the single-origin hypothesis) as essential for evolutionary theory.

Furthermore, Josiah Nott was the translator of Arthur de Gobineau's An Essay on the Inequality of the Human Races (1853–1855), which is one of the founding works of the group of studies that segregates society based on "race", in contrast to Boulainvilliers' (1658–1722) theory of races. Henri de Boulainvilliers opposed the Français (French people), alleged descendants of the Nordic Franks, and members of the aristocracy, to the Third Estate, considered to be indigenous Gallo-Roman people who were subordinated by the Franks by right of conquest. Gobineau, meanwhile, made three main divisions between races, based not on colour but on climatic conditions and geographic location, and which privileged the "Aryan" race. 

In 1873, Paul Broca (1824–1880) found the same pattern described by Samuel Morton's Crania Americana by weighing brains at autopsy. Other historical studies alleging a Black-White difference in brain size include Bean (1906), Mall, (1909), Pearl, (1934) and Vint (1934).

William Z. Ripley's map of the "cephalic index" in Europe, from The Races of Europe (1899).

 

Furthermore, Georges Vacher de Lapouge's racial classification ("Teutonic", "Alpine" and "Mediterranean") was re-used by William Z. Ripley (1867–1941) in The Races of Europe (1899), who even made a map of Europe according to the alleged cephalic index of its inhabitants.

In Germany, Rudolf Virchow launched a study of craniometry, which gave surprising results according to contemporary theories on the "Aryan race", leading Virchow to denounce the "Nordic mysticism" in the 1885 Anthropology Congress in Karlsruhe.

Josef Kollmann, a collaborator of Virchow, stated in the same congress that the people of Europe, be them German, Italian, English or French, belonged to a "mixture of various races," furthermore declaring that the "results of craniology" led to "struggle against any theory concerning the superiority of this or that European race" on others.

Virchow later rejected measure of skulls as legitimate means of taxinomy. Paul Kretschmer quoted an 1892 discussion with him concerning these criticisms, also citing Aurel von Törok's 1895 work, who basically proclaimed the failure of craniometry.

Craniometry, phrenology and physiognomy

Craniometry was also used in phrenology, which purported to determine character, personality traits, and criminality on the basis of the shape of the head and thus of the skull. At the turn of the 19th century, Franz Joseph Gall (1758–1822) developed "cranioscopy" (Ancient Greek kranion: skull, scopos: vision), a method to determine the personality and development of mental and moral faculties on the basis of the external shape of the skull.

Cranioscopy was later renamed to phrenology (phrenos: mind, logos: study) by his student Johann Spurzheim (1776–1832), who wrote extensively on the "Drs. Gall and Spurzheim's physiognomical System." Physiognomy claimed a correlation between physical features (especially facial features) and character traits.

It was made famous by Cesare Lombroso (1835–1909), the founder of anthropological criminology, who claimed to be able to scientifically identify links between the nature of a crime and the personality or physical appearance of the offender. The originator of the concept of a "born criminal" and arguing in favor of biological determinism, Lombroso tried to recognize criminals by measurements of their bodies.

He concluded that skull and facial features were clues to genetic criminality, and that these features could be measured with craniometers and calipers with the results developed into quantitative research. A few of the 14 identified traits of a criminal included large jaws, forward projection of jaw, low sloping forehead; high cheekbones, flattened or upturned nose; handle-shaped ears; hawk-like noses or fleshy lips; hard shifty eyes; scanty beard or baldness; insensitivity to pain; long arms, and so on.

Criticisms and revival of past cranial theories in the 20th century

An 1839 drawing by Samuel George Morton of "a Negro head… a Caucasian skull… a Mongol head."

 

After being a main influence of US white supremacists, William Ripley's The Races of Europe (1899) was eventually rewritten in 1939, just before World War II, by Harvard physical anthropologist Carleton S. Coon.

J. Philippe Rushton, psychologist and author of the controversial work Race, Evolution and Behavior (1995), reanalyzed Gould's retabulation in 1989, and argued that Samuel Morton, in his 1839 book Crania Americana, had shown a pattern of decreasing brain size proceeding from East Asians, Europeans, and Africans.

In his 1995 book Race, Evolution, and Behavior, he alleged an average endocranial volume of 1,364 cm³ for East Asians, 1,347 for white caucasians and 1,268 for black Africans. Other similar claims were previously made by Ho et al. (1980), who measured 1,261 brains at autopsy, and Beals et al. (1984), who measured approximately 20,000 skulls, finding the same East Asian → European → African pattern. However, in the same article Beals explicitly warns against using the findings as indicative of racial traits, "If one merely lists such means by geographical region or race, causes of similarity by genogroup and ecotype are hopelessly confounded". Rushton's findings have also been criticized for questionable methodology. Such as lumping in African-Americans with equatorial Africans, who generally have smaller crania as people from hot climates often have slightly smaller crania, in craniometry studies. He has also compared equatorial Africans from the poorest and least educated areas of Africa against Asians from the wealthiest and most educated areas of Asia and areas with colder climates which generally induce larger cranium sizes in evolution. According to Zack Cernovsky, from one of Rushton's own study emerges that the average cranial capacity for North American blacks is similar to the average for Caucasians from comparable climatic zones, however a previous work by Rushton showed appreciable differences in cranial capacity between North Americans of different race. This is consistent with the findings of Z. Z. Cernovsky that people from different climates tend to have minor differences in brain size. Though differences in size does not necessarily imply differences in intelligence. Though women tend to have smaller brains than men they also have more neural complexity and loading in certain areas of the brain than men.

Modern use

More direct measurements involve examinations of brains from corpses, or more recently, imaging techniques such as MRI, which can be used on living persons. Such measurements are used research on neuroscience and intelligence.

Brain volume data and other craniometric data are used in mainstream science to compare modern-day animal species, and to analyze the evolution of the human species in archaeology.

Measurements of the skull based on specific anatomical reference points are used in both forensic facial reconstruction and portrait sculpture.