Exaptation

From Wikipedia, the free encyclopedia

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

Exaptation and the related term co-option describe a shift in the function of a trait during evolution. For example, a trait can evolve because it served one particular function, but subsequently it may come to serve another. Exaptations are common in both anatomy and behaviour.

Bird feathers are a classic example. Initially they may have evolved for temperature regulation, but later were adapted for flight. When feathers were first used to aid in flight, that was an exaptive use. They have since then been shaped by natural selection to improve flight, so in their current state they are best regarded as adaptations for flight. So it is with many structures that initially took on a function as exaptations, once molded for that new function they become adapted for that function

Interest in exaptation relates to both the process and products of evolution: the process that creates complex traits and the products (functions, anatomical structures, biochemicals, etc.) that may be imperfectly developed. The term "exaptation" was proposed by Stephen Jay Gould and Elisabeth Vrba, as a replacement for 'pre-adaptation', which they considered to be a teleologically loaded term.

History and definitions

Charles Darwin

The idea that the function of a trait might shift during its evolutionary history originated with Charles Darwin (Darwin 1859). For many years the phenomenon was labeled "preadaptation", but since this term suggests teleology in biology, appearing to conflict with natural selection, it has been replaced by the term exaptation.

The idea had been explored by several scholars when in 1982 Stephen Jay Gould and Elisabeth Vrba introduced the term "exaptation". However, this definition had two categories with different implications for the role of adaptation.

(1) A character, previously shaped by natural selection for a particular function (an adaptation), is coopted for a new use—cooptation. (2) A character whose origin cannot be ascribed to the direct action of natural selection (a nonaptation), is coopted for a current use—cooptation. (Gould and Vrba 1982, Table 1)

The definitions are silent as to whether exaptations had been shaped by natural selection after cooption, although Gould and Vrba cite examples (e.g., feathers) of traits shaped after cooption. Note that the selection pressure upon a trait is likely to change if it is (especially, primarily or solely) used for a new purpose, potentially initiating a different evolutionary trajectory.

To avoid these ambiguities, Buss et al. (1998) suggested the term "co-opted adaptation", which is limited to traits that evolved after cooption. However, the commonly used terms of "exaptation" and "cooption" are ambiguous in this regard.

Preadaptation

In some circumstances, the "pre-" in preadaptation can be interpreted as applying, for non-teleological reasons, prior to the adaptation itself, creating a meaning for the term that is distinct from exaptation. For example, future environments (say, hotter or drier ones), may resemble those already encountered by a population at one of its current spatial or temporal margins. This is not actual foresight, but rather the luck of having adapted to a climate which later becomes more prominent. Cryptic genetic variation may have the most strongly deleterious mutations purged from it, leaving an increased chance of useful adaptations, but this represents selection acting on current genomes with consequences for the future, rather than foresight.

Function may not always come before form: developed structures could change or alter the primary functions they were intended for due to some structural or historical cause.

Examples

Bird feathers of various colors

Exaptations include the co-option of feathers, which initially evolved for heat regulation, for display, and later for use in bird flight. Another example is the lungs of many basal fish, which evolved into the lungs of terrestrial vertebrates but also underwent exaptation to become the gas bladder, a buoyancy control organ, in derived fish. A third is the repurposing of two of the three bones in the reptilian jaw to become the malleus and incus of the mammalian ear, leaving the mammalian jaw with just one hinge.

A behavioural example pertains to subdominant wolves licking the mouths of lead wolves as a sign of submissiveness. (Similarly, dogs, which are wolves who through a long process were domesticated, lick the faces of their human owners.) This trait can be explained as an exaptation of wolf pups licking the faces of adults to encourage them to regurgitate food.

Arthropods provide the earliest identifiable fossils of land animals, from about 419 million years ago in the Late Silurian, and terrestrial tracks from about 450 million years ago appear to have been made by arthropods. Arthropods were well pre-adapted to colonize land, because their existing jointed exoskeletons provided support against gravity and mechanical components that could interact to provide levers, columns and other means of locomotion that did not depend on submergence in water.

Metabolism can be considered an important part of exaptation. As one of the oldest biological systems and being central to life on the Earth, studies have shown that metabolism may be able to use exaptation in order to be fit, given some new set of conditions or environment. Studies have shown that up to 44 carbon sources are viable for metabolism to successfully take place and that any one adaptation in these specific metabolic systems is due to multiple exaptations. Taking this perspective, exaptations are important in the origination of adaptations in general. A recent example comes from Richard Lenski's E. coli long-term evolution experiment, in which aerobic growth on citrate arose in one of twelve populations after 31,000 generations of evolution. Genomic analysis by Blount and colleagues showed that this novel trait was due to a gene duplication that caused a citrate transporter that is normally expressed only under anoxic conditions to be expressed under oxic conditions, thus exapting it for aerobic use. Metabolic systems have the potential to innovate without adaptive origins.

Gould and Brosius took the concept of exaptation to the genetic level. It is possible to look at a retroposon, originally thought to be simply junk DNA, and deduce that it may have gotten a new function to be termed as an exaptation. Given an emergency situation in the past, a species may have used junk DNA for a useful purpose in order to evolve and be able to survive. This may have occurred with mammalian ancestors when confronted with a large mass extinction about 250 million years ago and substantial increase in the level of oxygen in Earth's atmosphere. More than 100 loci have been found to be conserved only among mammalian genomes and are thought to have essential roles in the generation of features such as the placenta, diaphragm, mammary glands, neocortex, and auditory ossicles. It is believed that as a result of exaptation, or making previously "useless" DNA into DNA that could be used in order to increase survival chance, mammals were able to generate new brain structures as well as behavior to better survive the mass extinction and adapt to new environments. Similarly, viruses and their components have been repeatedly exapted for host functions. The functions of exapted viruses typically involve either defense from other viruses or cellular competitors or transfer of nucleic acids between cells, or storage functions. Koonin and Krupovic suggested that virus exaptation can reach different depths, from recruitment of a fully functional virus to exploitation of defective, partially degraded viruses, to utilization of individual virus proteins.

Adaptation and exaptation cycle

It was speculated by Gould and Vrba in one of the first papers written about exaptation, that when an exaptation arises, it may not be perfectly suited for its new role and may therefore develop new adaptations to promote its use in a better manner. In other words, the beginning of developing a particular trait starts out with a primary adaptation toward a fit or specific role, followed by a primary exaptation (a new role is derived using the existing feature but may not be perfect for it), which in turn leads to the development of a secondary adaptation (the feature is improved by natural selection for better performance), promoting further development of an exaptation, and so forth.

Once again, feathers are an important example, in that they may have first been adapted for thermoregulation and with time became useful for catching insects, and therefore served as a new feature for another benefit. For instance, large contour feathers with specific arrangements arose as an adaptation for catching insects more successfully, which eventually led to flight, since the larger feathers served better for that purpose.

Implications

Evolution of complex traits

One of the challenges to Darwin's theory of evolution was explaining how complex structures could evolve gradually, given that their incipient forms may have been inadequate to serve any function. As George Jackson Mivart (a critic of Darwin) pointed out, 5 percent of a bird wing would not be functional. The incipient form of complex traits would not have survived long enough to evolve to a useful form.

As Darwin elaborated in the last edition of The Origin of Species, many complex traits evolved from earlier traits that had served different functions. By trapping air, primitive wings would have enabled birds to efficiently regulate their temperature, in part, by lifting up their feathers when too warm. Individual animals with more of this functionality would more successfully survive and reproduce, resulting in the proliferation and intensification of the trait.

Eventually, feathers became sufficiently large to enable some individuals to glide. These individuals would in turn more successfully survive and reproduce, resulting in the spread of this trait because it served a second and still more beneficial function: that of locomotion. Hence, the evolution of bird wings can be explained by a shifting in function from the regulation of temperature to flight.

Jury-rigged design

Darwin explained how the traits of living organisms are well-designed for their environment, but he also recognized that many traits are imperfectly designed. They appear to have been made from available material, that is, jury-rigged. Understanding exaptations may suggest hypotheses regarding subtleties in the adaptation. For instance, that feathers evolved initially for thermal regulation may help to explain some of their features unrelated to flight (Buss et al., 1998). However, this is readily explained by the fact that they serve a dual purpose.

Some of the chemical pathways for physical pain and pain from social exclusion overlap. The physical pain system may have been co-opted to motivate social animals to respond to threats to their inclusion in the group.

Evolution of technology

Exaptation has received increasing attention in innovation and management studies inspired by evolutionary dynamics, where it has been proposed as a mechanism that drives the serendipitous expansion of technologies and products in new domains.

Adaptationism

From Wikipedia, the free encyclopedia

Adaptationism, also known as functionalism, is the Darwinian view that many physical and psychological traits of organisms are evolved adaptations. Pan-adaptationism is the strong form of this, deriving from the early 20th century modern synthesis, that all traits are adaptations, a view now shared by few biologists. Adaptationists perform research to try to distinguish adaptations (e.g., the umbilical cord) from byproducts (e.g., the belly button) or random variation (e.g., convex or concave shape of the belly button). George Williams' Adaptation and Natural Selection (1966) was highly influential in its development, defining some of the heuristics used to identify adaptations.

Criteria to identify a trait as an adaptation

Adaptationism is an approach to studying the evolution of form and function. It attempts to frame the existence and persistence of traits, assuming that each of them arose independently and improved the reproductive success of the organism's ancestors. A trait is an adaptation if it fulfils the following criteria:

1. The trait is a variation of an earlier form.
2. The trait is heritable through the transmission of genes.
3. The trait enhances reproductive success.

Constraints on the power of evolution

Genetic constraints

Genetic reality provides constraints on the power of random mutation followed by natural selection.

With pleiotropy, some genes control multiple traits, so that adaptation of one trait is impeded by effects on other traits that are not necessarily adaptive. Selection that influences epistasis is a case where the regulation or expression of one gene, depends on one or several others. This is true for a good number of genes though to differing extents. The reason why this leads to muddied responses is that selection for a trait that is epistatically based can mean that an allele for a gene that is epistatic when selected would happen to affect others. This leads to the coregulation of others for a reason other than there is an adaptive quality to each of those traits. Like with pleiotropy, traits could reach fixation in a population as a by-product of selection for another.

In the context of development the difference between pleiotropy and epistasis is not so clear but at the genetic level the distinction is more clear. With these traits as being by-products of others it can ultimately be said that these traits evolved but not that they necessarily represent adaptations.

Polygenic traits are controlled by a number of separate genes. Many traits are polygenic, for example human height. To drastically change a polygenic trait is likely to require multiple changes.

Anatomical constraints

Anatomical constraints are features of organism's anatomy that are prevented from change by being constrained in some way. When organisms diverge from a common ancestor and inherit certain characteristics which become modified by natural selection of mutant phenotypes, it is as if some traits are locked in place and are unable to change in certain ways. Some textbook anatomical constraints often include examples of structures that connect parts of the body together though a physical link.

These links are hard if not impossible to break because evolution usually requires that anatomy be formed by small consecutive modifications in populations through generations. In his book, Why We Get Sick, Randolph Nesse uses the "blind spot" in the vertebrate eye (caused by the nerve fibers running through the retina) as an example of this. He argues that natural selection has come up with an elaborate work-around of the eyes wobbling back-and-forth to correct for this, but vertebrates have not found the solution embodied in cephalopod eyes, where the optic nerve does not interrupt the view. See also: Evolution of the eye.

Another example is the cranial nerves in tetrapods. In early vertebrate evolution, sharks, skates, and rays (collectively Chondrichthyes), the cranial nerves run from the part of the brain that interprets sensory information, and radiate out towards the organs that produce those sensations. In tetrapods, however, and mammals in particular, the nerves take an elaborate winding path through the cranium around structures that evolved after the common ancestor with sharks.

Debate with structuralism

Further information: Structuralism and Alternatives to evolution by natural selection

Adaptationism is sometimes characterized by critics as an unsubstantiated assumption that all or most traits are optimal adaptations. Structuralist critics (most notably Richard Lewontin and Stephen Jay Gould in their "spandrel" paper) contend that the adaptationists have over-emphasized the power of natural selection to shape individual traits to an evolutionary optimum. Adaptationists are sometimes accused by their critics of using ad hoc "just-so stories". The critics, in turn, have been accused of misrepresentation (Straw man argumentation), rather than attacking the actual statements of supposed adaptationists.

Adaptationist researchers respond by asserting that they, too, follow George Williams' depiction of adaptation as an "onerous concept" that should only be applied in light of strong evidence. This evidence can be generally characterized as the successful prediction of novel phenomena based on the hypothesis that design details of adaptations should fit a complex evolved design to respond to a specific set of selection pressures. In evolutionary psychology, researchers such as Leda Cosmides, John Tooby, and David Buss contend that the bulk of research findings that were uniquely predicted through adaptationist hypothesizing comprise evidence of the methods' validity.

Purpose and function

There are philosophical issues with the way biologists speak of function, effectively invoking teleology, the purpose of an adaptation.

Function

Main article: Function (biology)

To say something has a function is to say something about what it does for the organism. It also says something about its history: how it has come about. A heart pumps blood: that is its function. It also emits sound, which is considered to be an ancillary side-effect, not its function. The heart has a history (which may be well or poorly understood), and that history is about how natural selection formed and maintained the heart as a pump. Every aspect of an organism that has a function has a history. Now, an adaptation must have a functional history: therefore we expect it must have undergone selection caused by relative survival in its habitat. It would be quite wrong to use the word adaptation about a trait which arose as a by-product.

It is widely regarded as unprofessional for a biologist to say something like "A wing is for flying," although that is their normal function. A biologist would be conscious that sometime in the remote past feathers on a small dinosaur had the function of retaining heat, and that later many wings were not used for flying (e.g. penguins, ostriches). So, the biologist would rather say that the wings on a bird or an insect usually had the function of aiding flight. That would carry the connotation of being an adaptation with a history of evolution by natural selection.

Teleology

Main article: Teleology in biology

Teleology was introduced into biology by Aristotle to describe the adaptedness of organisms. Biologists have found the implications of purposefulness awkward as they suggest supernatural intention, an aspect of Plato's thinking which Aristotle rejected. A similar term, teleonomy, was suggested by Colin Pittendrigh in 1958; it grew out of cybernetics and self-organising systems. Biologists of the 1960s such as Ernst Mayr, George C. Williams and Jacques Monod used it as a less loaded alternative. However, the discomfort remains. On the one hand, adaptation is obviously purposeful: natural selection chooses what works and eliminates what does not. On the other hand, biologists want to deny conscious purpose in evolution. The dilemma gave rise to a famous joke by the evolutionary biologist Haldane: "Teleology is like a mistress to a biologist: he cannot live without her but he's unwilling to be seen with her in public.'" David Hull commented that Haldane's mistress "has become a lawfully wedded wife. Biologists no longer feel obligated to apologize for their use of teleological language; they flaunt it. The only concession which they make to its disreputable past is to rename it 'teleonomy'."

 

Steven Pinker

From Wikipedia, the free encyclopedia

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

 

Steven Pinker
Pinker in 2011
Born	Steven Arthur Pinker September 18, 1954 (age 67) Montreal, Quebec, Canada
Nationality	Canada US
Education	McGill University (BA) Harvard University (PhD)
Notable work	The Language Instinct (1994) How the Mind Works (1997) The Blank Slate (2002) The Better Angels of Our Nature (2011) Enlightenment Now (2018)
Spouse(s)	Nancy Etcoff ​ ​ (m. 1980; div. 1992)​ Ilavenil Subbiah ​ ​ (m. 1995; div. 2006)​ Rebecca Goldstein ​ (m. 2007)​
Awards	Troland Award (1993, National Academy of Sciences), Henry Dale Prize (2004, Royal Institution), Walter P. Kistler Book Award (2005), Humanist of the Year award (2006, issued by the AHA), George Miller Prize (2010, Cognitive Neuroscience Society), Richard Dawkins Award (2013)
Scientific career
Fields	Evolutionary psychology experimental psychology cognitive science psycholinguistics visual cognition
Institutions	Harvard University Massachusetts Institute of Technology New College of the Humanities
Thesis	The Representation of Three-dimensional Space in Mental Images (1979)
Doctoral advisor	Stephen Kosslyn
Influences	Noam Chomsky · Jerry Fodor · Richard Dawkins · Robert Trivers · Leda Cosmides · John Tooby · Ray Jackendoff · Daniel Dennett · Judith Rich Harris · Donald Symons · Peter Singer · Thomas Schelling · Norbert Elias · Roy Baumeister
Steven Pinker's voice (0:27) Menu 0:00 from the BBC program Desert Island Discs, June 30, 2013
Website	stevenpinker.com

Steven Arthur Pinker (born September 18, 1954) is a Canadian-American cognitive psychologist, psycholinguist, popular science author and public intellectual. He is an advocate of evolutionary psychology and the computational theory of mind

Pinker is the Johnstone Family Professor of Psychology at Harvard University, and his academic specializations are visual cognition and developmental linguistics. His experimental subjects include mental imagery, shape recognition, visual attention, children's language development, regular and irregular phenomena in language, the neural bases of words and grammar, as well as the psychology of cooperation and communication, including euphemism, innuendo, emotional expression, and common knowledge. He has written two technical books that proposed a general theory of language acquisition and applied it to children's learning of verbs. In particular, his work with Alan Prince published in 1989 critiqued the connectionist model of how children acquire the past tense of English verbs, positing that children use default rules, such as adding -ed to make regular forms, sometimes in error, but are obliged to learn irregular forms one by one.

Pinker is also the author of eight books for general audiences. The Language Instinct (1994), How the Mind Works (1997), Words and Rules (2000), The Blank Slate (2002), and The Stuff of Thought (2007) describe aspects of psycholinguistics and cognitive science, and include accounts of his own research, positing that language is an innate behavior shaped by natural selection and adapted to our communication needs. Pinker's The Sense of Style (2014) is a general language-oriented style guide. Pinker's book The Better Angels of Our Nature (2011) posits that violence in human societies has generally steadily declined over time, and identifies six major trends and five historical forces of this decline. Enlightenment Now (2018) uses social science data to show a general improvement of the human condition over recent history.

In 2004, Pinker was named in Time's "The 100 Most Influential People in the World Today", and in the years 2005, 2008, 2010, and 2011 in Foreign Policy's list of "Top 100 Global Thinkers". Pinker was also included in Prospect Magazine's top 10 "World Thinkers" in 2013. He has won awards from the American Psychological Association, the National Academy of Sciences, the Royal Institution, the Cognitive Neuroscience Society, and the American Humanist Association. He delivered the Gifford Lectures at the University of Edinburgh in 2013. He has served on the editorial boards of a variety of journals, and on the advisory boards of several institutions. Pinker was the chair of the Usage Panel of the American Heritage Dictionary from 2008 to 2018.

Biography

Pinker was born in Montreal, Quebec, in 1954, to a middle-class Jewish family. His grandparents emigrated to Canada from Poland and Romania in 1926, and owned a small necktie factory in Montreal. His father was a lawyer. His mother eventually became a high-school vice-principal. His brother is a policy analyst for the Canadian government, while his sister, Susan Pinker, is a psychologist and writer who authored The Sexual Paradox and The Village Effect.

Pinker married Nancy Etcoff in 1980 and they divorced in 1992; he married again in 1995 and again divorced. His third wife, whom he married in 2007, is the novelist and philosopher Rebecca Goldstein. He has two stepdaughters: the novelist Yael Goldstein Love and the poet Danielle Blau.

Pinker graduated from Dawson College in 1973. He graduated from McGill University in 1976 with a Bachelor of Arts in psychology, then did doctoral studies in experimental psychology at Harvard University under Stephen Kosslyn, receiving a Ph.D. in 1979. He did research at the Massachusetts Institute of Technology for a year, then became a professor at Harvard and then Stanford University.

From 1982 until 2003, Pinker taught at the Department of Brain and Cognitive Sciences at MIT, was the co-director of the center for Cognitive science (1985–1994), and eventually became the director of the center for Cognitive neuroscience (1994–1999), taking a one-year sabbatical at the University of California, Santa Barbara, in 1995–96. Since 2003, he has been serving as the Johnstone Family Professor of Psychology at Harvard and between 2008 and 2013 he also held the title of Harvard College Professor in recognition of his dedication to teaching. He currently gives lectures as a visiting professor at the New College of the Humanities, a private college in London

Pinker adopted atheism at 13, but at various times was a serious "cultural Jew."  Linguistic career

Pinker's research on visual cognition, begun in collaboration with his thesis adviser, Stephen Kosslyn, showed that mental images represent scenes and objects as they appear from a specific vantage point (rather than capturing their intrinsic three-dimensional structure), and thus correspond to the neuroscientist David Marr's theory of a "two-and-a-half-dimensional sketch." He also showed that this level of representation is used in visual attention, and in object recognition (at least for asymmetrical shapes), contrary to Marr's theory that recognition uses viewpoint-independent representations.

In psycholinguistics, Pinker became known early in his career for promoting computational learning theory as a way to understand language acquisition in children. He wrote a tutorial review of the field followed by two books that advanced his own theory of language acquisition, and a series of experiments on how children acquire the passive, dative, and locative constructions. These books were Language Learnability and Language Development (1984), in Pinker's words "outlin[ing] a theory of how children acquire the words and grammatical structures of their mother tongue", and Learnability and Cognition: The Acquisition of Argument Structure (1989), in Pinker's words "focus[ing] on one aspect of this process, the ability to use different kinds of verbs in appropriate sentences, such as intransitive verbs, transitive verbs, and verbs taking different combinations of complements and indirect objects". He then focused on verbs of two kinds that illustrate what he considers to be the processes required for human language: retrieving whole words from memory, like the past form of the irregular verb "bring", namely "brought"; and using rules to combine (parts of) words, like the past form of the regular verb "walk", namely "walked".

In 1988 Pinker and Alan Prince published a critique of a connectionist model of the acquisition of the past tense (a textbook problem in language acquisition), followed by a series of studies of how people use and acquire the past tense. This included a monograph on children's regularization of irregular forms and his popular 1999 book, Words and Rules: The Ingredients of Language. Pinker argued that language depends on two things, the associative remembering of sounds and their meanings in words, and the use of rules to manipulate symbols for grammar. He presented evidence against connectionism, where a child would have to learn all forms of all words and would simply retrieve each needed form from memory, in favour of the older alternative theory, the use of words and rules combined by generative phonology. He showed that mistakes made by children indicate the use of default rules to add suffixes such as "-ed": for instance 'breaked' and 'comed' for 'broke' and 'came'. He argued that this shows that irregular verb-forms in English have to be learnt and retrieved from memory individually, and that the children making these errors were predicting the regular "-ed" ending in an open-ended way by applying a mental rule. This rule for combining verb stems and the usual suffix can be expressed as V_past → V_stem + d, where V is a verb and d is the regular ending. Pinker further argued that since the ten most frequently occurring English verbs (be, have, do, say, make ... ) are all irregular, while 98.2% of the thousand least common verbs are regular, there is a "massive correlation" of frequency and irregularity. He explains this by arguing that every irregular form, such as 'took', 'came' and 'got', has to be committed to memory by the children in each generation, or else lost, and that the common forms are the most easily memorized. Any irregular verb that falls in popularity past a certain point is lost, and all future generations will treat it as a regular verb instead.

In 1990, Pinker, with Paul Bloom, published a paper arguing that the human language faculty must have evolved through natural selection. The article provided arguments for a continuity based view of language evolution, contrary to then current discontinuity based theories that see language as suddenly appearing with the advent of Homo sapiens as a kind of evolutionary accident. This discontinuity based view was prominently argued by two of the main authorities, linguist Noam Chomsky and Stephen Jay Gould. The paper became widely cited and created renewed interest in the evolutionary prehistory of language, and has been credited with shifting the central question of the debate from "did language evolve?" to "how did language evolve". The article also presaged Pinker's argument in The Language Instinct.

In 2007, Pinker gave his expert interpretation as a linguist of the wording of a federal law pertaining to the enticement of minors into illegal sex acts via the internet. This opinion was provided to Alan Dershowitz, a personal friend of Pinker's, who was the defense attorney for Jeffrey Epstein, resulting in a plea deal in which all federal sex trafficking charges against Epstein were dropped. In 2019, Pinker stated that he was unaware of the nature of the charges against Epstein, and that he engaged in an unpaid favor for his Harvard colleague Alan Dershowitz, as he had regularly done. He stated that he regrets writing the letter. Pinker says he never received money from Epstein and met with him three times over more than a dozen years, and said he could never stand Epstein and tried to keep his distance.

Popularization of science

Human cognition and natural language

Main articles: The Language Instinct, Words and Rules, How the Mind Works, The Blank Slate, and The Stuff of Thought

Pinker's 1994 The Language Instinct was the first of several books to combine cognitive science with behavioral genetics and evolutionary psychology. It introduces the science of language and popularizes Noam Chomsky's theory that language is an innate faculty of mind, with the controversial twist that the faculty for language evolved by natural selection as an adaptation for communication. Pinker criticizes several widely held ideas about language – that it needs to be taught, that people's grammar is poor and getting worse with new ways of speaking, the Sapir–Whorf hypothesis that language limits the kinds of thoughts a person can have, and that other great apes can learn languages. Pinker sees language as unique to humans, evolved to solve the specific problem of communication among social hunter-gatherers. He argues that it is as much an instinct as specialized adaptative behavior in other species, such as a spider's web-weaving or a beaver's dam-building.

Pinker states in his introduction that his ideas are "deeply influenced" by Chomsky; he also lists scientists whom Chomsky influenced to "open up whole new areas of language study, from child development and speech perception to neurology and genetics" — Eric Lenneberg, George Miller, Roger Brown, Morris Halle and Alvin Liberman. Brown mentored Pinker through his thesis; Pinker stated that Brown's "funny and instructive" book Words and Things (1958) was one of the inspirations for The Language Instinct.

There has been debate about the explanatory adequacy of the theory. By 2015, the nativist views of Pinker and Chomsky had a number of challenges on the grounds that they had incorrect core assumptions and were inconsistent with research evidence from psycholinguistics and child language acquisition. The reality of Pinker's proposed language instinct, and the related claim that grammar is innate and genetically based, has been contested by linguists such as Geoffrey Sampson in his 1997 book, Educating Eve: The 'Language Instinct' Debate'  Sampson argues that "while it may seem attractive to argue the nature side of the 'nature versus nurture' debate, the nurture side may better support the creativity and nobility of the human mind." Sampson denies there is a language instinct, and argues that children can learn language because people can learn anything. Others have sought a middle ground between Pinker's nativism and Sampson's culturalism.

The assumptions underlying the nativist view have also been questioned in Jeffrey Elman's Rethinking Innateness: A Connectionist Perspective on Development, which defends the connectionist approach that Pinker attacked. In his 1996 book Impossible Minds, the machine intelligence researcher Igor Aleksander calls The Language Instinct excellent, and argues that Pinker presents a relatively soft claim for innatism, accompanied by a strong dislike of the 'Standard Social Sciences Model' or SSSM (Pinker's term), which supposes that development is purely dependent on culture. Further, Aleksander writes that while Pinker criticises some attempts to explain language processing with neural nets, Pinker later makes use of a neural net to create past tense verb forms correctly. Aleksander concludes that while he doesn't support the SSSM, "a cultural repository of language just seems the easy trick for an efficient evolutionary system armed with an iconic state machine to play."

Two other books, How the Mind Works (1997) and The Blank Slate (2002), broadly surveyed the mind and defended the idea of a complex human nature with many mental faculties that are genetically adaptive (Pinker is an ally of Daniel Dennett and Richard Dawkins in many disputes surrounding adaptationism). Another major theme in Pinker's theories is that human cognition works, in part, by combinatorial symbol-manipulation, not just associations among sensory features, as in many connectionist models. On the debate around The Blank Slate, Pinker called Thomas Sowell's book A Conflict of Visions "wonderful", and explained that "The Tragic Vision" and the "Utopian Vision" are the views of human nature behind right- and left-wing ideologies.

In Words and Rules: the Ingredients of Language (1999), Pinker argues from his own research that regular and irregular phenomena are products of computation and memory lookup, respectively, and that language can be understood as an interaction between the two. "Words and Rules" is also the title of an essay by Pinker outlining many of the topics discussed in the book. Critiqueing the book from the perspective of generative linguistics Charles Yang, in the London Review of Books, writes that "this book never runs low on hubris or hyperbole". The book's topic, the English past tense, is in Yang's view unglamorous, and Pinker's attempts at compromise risk being in no man's land between rival theories. Giving the example of German, Yang argues that irregular nouns in that language at least all belong to classes, governed by rules, and that things get even worse in languages that attach prefixes and suffixes to make up long 'words': they can't be learnt individually, as there are untold numbers of combinations. "All Pinker (and the connectionists) are doing is turning over the rocks at the base of the intellectual landslide caused by the Chomskian revolution."

In The Stuff of Thought (2007), Pinker looks at a wide range of issues around the way words related to thoughts on the one hand, and to the world outside ourselves on the other. Given his evolutionary perspective, a central question is how an intelligent mind capable of abstract thought evolved: how a mind adapted to Stone Age life could work in the modern world. Many quirks of language are the result.

Pinker is critical of theories about the evolutionary origins of language that argue that linguistic cognition might have evolved from earlier musical cognition. He sees language as being tied primarily to the capacity for logical reasoning, and speculates that human proclivity for music may be a spandrel — a feature not adaptive in its own right, but that has persisted through other traits that are more broadly practical, and thus selected for. In How the Mind Works, Pinker reiterates Immanuel Kant's view that music is not in itself an important cognitive phenomenon, but that it happens to stimulate important auditory and spatio-motor cognitive functions. Pinker compares music to "auditory cheesecake", stating that "As far as biological cause and effect is concerned, music is useless". This argument has been rejected by Daniel Levitin and Joseph Carroll, experts in music cognition, who argue that music has had an important role in the evolution of human cognition. In his book This Is Your Brain On Music, Levitin argues that music could provide adaptive advantage through sexual selection, social bonding, and cognitive development; he questions the assumption that music is the antecedent to language, as opposed to its progenitor, noting that many species display music-like habits that could be seen as precursors to human music.

Pinker has also been critical of "whole language" reading instruction techniques, stating in How the Mind Works, "... the dominant technique, called 'whole language,' the insight that [spoken] language is a naturally developing human instinct has been garbled into the evolutionarily improbable claim that reading is a naturally developing human instinct." In the appendix to the 2007 reprinted edition of The Language Instinct, Pinker cited Why Our Children Can't Read by cognitive psychologist Diane McGuinness as his favorite book on the subject and noted:

One raging public debate involving language went unmentioned in The Language Instinct: the "reading wars," or dispute over whether children should be explicitly taught to read by decoding the sounds of words from their spelling (loosely known as "phonics") or whether they can develop it instinctively by being immersed in a text-rich environment (often called "whole language"). I tipped my hand in the paragraph in [the sixth chapter of the book] which said that language is an instinct but reading is not. Like most psycholinguists (but apparently unlike many school boards), I think it's essential for children to be taught to become aware of speech sounds and how they are coded in strings of letters.

The Better Angels of Our Nature

Main article: The Better Angels of Our Nature

 

Violence in the middle ages: detail from "Mars" in Das Mittelalterliche Hausbuch, c. 1475 – 1480. The image is used by Pinker in The Better Angels of Our Nature, with the comment "as the Housebook illustrations suggest, [the knights] did not restrict their killing to other knights".

In The Better Angels of Our Nature, published in 2011, Pinker argues that violence, including tribal warfare, homicide, cruel punishments, child abuse, animal cruelty, domestic violence, lynching, pogroms, and international and civil wars, has decreased over multiple scales of time and magnitude. Pinker considers it unlikely that human nature has changed. In his view, it is more likely that human nature comprises inclinations toward violence and those that counteract them, the "better angels of our nature". He outlines six "major historical declines of violence" that all have their own socio/cultural/economic causes:

1. "The Pacification Process" – The rise of organized systems of government has a correlative relationship with the decline in violent deaths. As states expand they prevent tribal feuding, reducing losses.
2. "The Civilizing Process" – Consolidation of centralized states and kingdoms throughout Europe results in the rise of criminal justice and commercial infrastructure, organizing previously chaotic systems that could lead to raiding and mass violence.
3. "The Humanitarian Revolution" – The 18th to 20th century abandonment of institutionalized violence by the state (breaking on the wheel, burning at the stake). Suggests this is likely due to the spike in literacy after the invention of the printing press thereby allowing the proletariat to question conventional wisdom.
4. "The Long Peace" – The powers of 20th Century believed that period of time to be the bloodiest in history. This led to a largely peaceful 65-year period post World War I and World War II. Developed countries have stopped warring (against each other and colonially), adopted democracy, and this has led a massive decline (on average) of deaths.
5. "The New Peace" – The decline in organized conflicts of all kinds since the end of the Cold War.
6. "The Rights Revolutions" – The reduction of systemic violence at smaller scales against vulnerable populations (racial minorities, women, children, homosexuals, animals).

The book was welcomed by many critics and reviewers, who found its arguments convincing and its synthesis of a large volume of historical evidence compelling. It also aroused criticism on a variety of grounds, such as whether deaths per capita was an appropriate metric, Pinker's liberal humanism, excessive focus on Europe (though the book covers other areas), the interpretation of historical data, choice of methodologies, and its image of indigenous people

English writing style in the 21st century

In his seventh popular book, The Sense of Style: The Thinking Person's Guide to Writing in the 21st Century (2014), Pinker attempts to provide a writing style guide that is informed by modern science and psychology, because a long time has passed since William Strunk wrote Elements of Style.

Public debate

Pinker and Nils Brose speaking at a neuroscience conference.

Pinker is a frequent participant in public debates surrounding the contributions of science to contemporary society. Social commentators such as Ed West, author of The Diversity Illusion, consider Pinker important and daring in his willingness to confront taboos, as in The Blank Slate. According to West, the doctrine of tabula rasa remained accepted "as fact, rather than fantasy" a decade after the book's publication. West describes Pinker as "no polemicist, and he leaves readers to draw their own conclusions".

In January 2005, Pinker defended comments by then-President of Harvard University Lawrence Summers. Summers had speculated that "different availability of aptitude at the high end" may contribute to gender gaps in mathematics and science. In a debate between Pinker and Elizabeth Spelke on gender and science, Pinker argued in favor of the proposition that the gender difference in representation in elite universities was "explainable by some combination of biological differences in average temperaments and talents interacting with socialization and bias".

In 2007, Pinker was noted for having identified the rename of Phillip Morris to Altria as an "egregious example" of phonesthesia, with the company attempting to "switch its image from bad people who sell addictive carcinogens to a place or state marked by altruism and other lofty values".

In January 2009, Pinker wrote an article about the Personal Genome Project and its possible impact on the understanding of human nature in The New York Times. He discussed the new developments in epigenetics and gene-environment interactions in the afterword to the 2016 edition of his book "The Blank Slate".

In a November 2009 article for The New York Times, Pinker wrote a mixed review of Malcolm Gladwell's essays, criticizing his analytical methods. Gladwell replied, disputing Pinker's comments about the importance of IQ on teaching performance and by analogy, the effect, if any, of draft order on quarterback performance in the National Football League. Advanced NFL Stats addressed the issue statistically, siding with Pinker and showing that differences in methodology could explain the two men's differing opinions.

In an appearance for BBC World Service's "Exchanges At The Frontier" programme, an audience member questioned whether the virtuous developments in culture and human nature (documented in The Better Angels of Our Nature) could have expressed in our biology either through genetic or epigenetic expression. Pinker responded that it was unlikely since "some of the declines have occurred far too rapidly for them to be explicable by biological evolution which has a speed limit measured in generations, but crime can plummet in a span of 15 years and some of these humanitarian reforms like eliminating slavery and torture occurred in say 50 years". Helga Vierich and Cathryn Townsend wrote a critical review of Pinker's sweeping "civilizational" explanations for patterns of human violence and warfare in response to a lecture he gave at Cambridge University in September 2015.^[92]

In his 2018 book Enlightenment Now, Pinker posited that enlightenment rationality should be defended against attacks from both the political left and political right. The book received both positive and critical reviews. In a debate with Pinker, post-colonial theorist Homi Bhabha said that Pinker downplayed the immoral consequences of Enlightenment philosophy, such as inequality, slavery, imperialism, world wars, and genocide. Pinker responded that humanity, prior to the Enlightenment, had been characterized by poverty and disease. Pinker also wrote a detailed response to many such objections to the thesis presented in "Enlightenment Now".

In 2020, an open letter to the Linguistic Society of America requesting the removal of Pinker from its list of LSA Fellows and its list of media experts was signed by hundreds of academics. The letter accused Pinker of a "pattern of drowning out the voices of people suffering from racist and sexist violence, in particular in the immediate aftermath of violent acts and/or protests against the systems that created them", citing as examples six tweets and a phrase used in his 2011 book. Pinker said that through this letter he was being threatened by "a regime of intimidation that constricts the theatre of ideas Several academics criticized the letter and expressed strong support for Pinker. Conor Friedersdorf, writing in The Atlantic, criticized the letter for engaging in guilt by association and for creating a "chilling effect" on the speech of non-tenured academics, and Mother Jones called it "factually flawed" and "dishonest". The executive committee of the Linguistic Society of America issued a letter stating that the group "is committed to intellectual freedom and professional responsibility. It is not the mission of the Society to control the opinions of its members, nor their expression. Inclusion and civility are crucial to productive scholarly work. And inclusion means hearing (not necessarily accepting) all points of view, even those that may be objectionable to some."

Awards and distinctions

Pinker in Göttingen, 2010

Pinker was named one of Time's 100 most influential people in the world in 2004 and one of Prospect and Foreign Policy's 100 top public intellectuals in both years the poll was carried out, 2005 and 2008; in 2010 and 2011 he was named by Foreign Policy to its list of top global thinkers. In 2016, he was elected to the National Academy of Sciences.

His research in cognitive psychology has won the Early Career Award (1984) and Boyd McCandless Award (1986) from the American Psychological Association, the Troland Research Award (1993) from the National Academy of Sciences, the Henry Dale Prize (2004) from the Royal Institution of Great Britain, and the George Miller Prize (2010) from the Cognitive Neuroscience Society. He has also received honorary doctorates from the universities of Newcastle, Surrey, Tel Aviv, McGill, Simon Fraser University and the University of Tromsø. He was twice a finalist for the Pulitzer Prize, in 1998 and in 2003. Pinker received the Golden Plate Award of the American Academy of Achievement in 1999. On May 13, 2006, he received the American Humanist Association's Humanist of the Year award for his contributions to public understanding of human evolution.

Pinker has served on the editorial boards of journals such as Cognition, Daedalus, and PLOS One, and on the advisory boards of institutions for scientific research (e.g., the Allen Institute for Brain Science), free speech (e.g., the Foundation for Individual Rights in Education), the popularization of science (e.g., the World Science Festival and the Committee for Skeptical Inquiry), peace (e.g., the Peace Research Endowment), and secular humanism (e.g., the Freedom From Religion Foundation and the Secular Coalition for America).

From 2008 to 2018, Pinker chaired the Usage Panel of the American Heritage Dictionary. He wrote the essay on usage for the fifth edition of the Dictionary, published in 2011.

In February 2001, Pinker, "whose hair has long been the object of admiration, and envy, and intense study", was nominated by acclamation as the first member of the Luxuriant Flowing Hair Club for Scientists (LFHCfS) organized by the Annals of Improbable Research.

Bibliography

Books

• Language Learnability and Language Development (1984)
• Visual Cognition (1985)
• Connections and Symbols (1988)
• Learnability and Cognition: The Acquisition of Argument Structure (1989)
• Lexical and Conceptual Semantics (1992)
• The Language Instinct (1994)
• How the Mind Works (1997)
• Words and Rules: The Ingredients of Language (1999)
• The Blank Slate: The Modern Denial of Human Nature (2002)
• The Best American Science and Nature Writing (editor and introduction author, 2004)
• Hotheads (an extract from How the Mind Works, 2005) ISBN 978-0-14-102238-3
• The Stuff of Thought: Language as a Window into Human Nature (2007)
• The Better Angels of Our Nature: Why Violence Has Declined (2011)
• Language, Cognition, and Human Nature: Selected Articles (2013)
• The Sense of Style: The Thinking Person's Guide to Writing in the 21st Century (September 30, 2014)
• Enlightenment Now: The Case for Reason, Science, Humanism, and Progress (February 13, 2018)
• Rationality: What It Is, Why It Seems Scarce, Why It Matters (September 28, 2021)

Articles and essays

• Selective compilation of articles and other works, hosted at Harvard faculty pages
• Pinker, S. (1991). "Rules of Language". Science. 253 (5019): 530–535. Bibcode:1991Sci...253..530P. doi:10.1126/science.1857983. PMID 1857983.
• Ullman, M.; Corkin, S.; Coppola, M.; Hickok, G.; Growdon, J. H.; Koroshetz, W. J.; Pinker, S. (1997). "A neural dissociation within language: Evidence that the mental dictionary is part of declarative memory, and that grammatical rules are processed by the procedural system". Journal of Cognitive Neuroscience. 9 (2): 289–299. doi:10.1162/jocn.1997.9.2.266. PMID 23962016. S2CID 981612.
• Pinker, S. (2003) "Language as an adaptation to the cognitive niche" In M. Christiansen & S. Kirby (Eds.), Language evolution: States of the Art New York: Oxford University Press.
• Pinker, S. (2005) The Evolutionary Psychology of Religion
• Pinker, S. (2005). "So How Does the Mind Work?". Mind and Language. 20 (1): 1–24. doi:10.1111/j.0268-1064.2005.00274.x.
• Jackendoff, R.; Pinker, S. (2005). "The nature of the language faculty and its implications for evolution of language" (Reply to Fitch, Hauser, & Chomsky)". Cognition. 97 (2): 211–225. doi:10.1016/j.cognition.2005.04.006. S2CID 6571737.
• "In Defense of Dangerous Ideas". Steven Pinker. July 15, 2007. Archived from the original on August 7, 2017.
• Pinker, S. (2012). "The False Allure of Group Selection". Edge, June 19, 2012.
• Pinker, S. (2013). Science Is Not Your Enemy. New Republic, August 6, 2013.
• Pinker, S. (2014). "The Trouble With Harvard: The Ivy League is broken and only standardized tests can fix it". New Republic, September 4, 2014.