•Genes play a role in human behavior, instincts, and culture.
• The idea that genes shape behavior is controversial.
• Social scientists have argued that human beings do not have instincts.
•Behaviorism argues that we can be conditioned to prefer anything that gives us food.
•In linguistics, the first crack in the edifice was a book by Noam Chomsky, Syntactic structures, which argued that human language owes as much to instinct as it does to culture.
• Chomsky resurrected an old view of language, which had been described by Darwin as an ‘instinctive tendency to acquire an art’.
• The early psychologist William James was a fervent protagonist of the view that human behaviour showed evidence of more separate instincts than animals.
• By studying the way human beings speak, Chomsky concluded that there were underlying similarities to all languages that bore witness to a universal human grammar.
•Chomsky’s conjecture has been vindicated by evidence from many disciplines, which all conclude that humans have an innate language instinct.
• This is shown by the universality of language among human cultures, the consistency with which people follow grammatical rules, and children’s ability to impose rules on pidgin languages.
•Bickerton’s hypothesis is supported by the study of sign language.
• In one case, in Nicaragua, special schools for the deaf led to the invention of a whole new language.
• The schools taught lip-reading with little success, but in the playground the children brought together various hand signs they used at home and established a crude pidgin language.
• Within a few years, as younger children learnt this pidgin, it was transformed into a true sign language with all the complexity of spoken languages.
• A sensitive period during which something can be learnt is a feature of many animals’ instincts and human beings as well.
•The idea that language can shape the brain, rather than vice versa, has been slow to die.
• Even though canonical case histories have been exposed as frauds, the notion survives in many social sciences.
• Evidence for the language instinct comes from many sources, including detailed studies of how children develop language skills.
• Neurological and genetic evidence suggests that there is a strong link between language and certain parts of the brain.
•A gene on chromosome 7 has been linked to a strong heritability for specific language impairment (SLI).
• SLI is a condition that affects linguistic ability without apparently affecting intelligence.
• The argument over what SLI is rages between those who think it is merely a general problem with the brain that affects many aspects of language-producing ability, and those who think there is something more intriguing going on with grammar understanding and usage.
•Gopnik hypothesises that people with SLI store English plurals in their minds as separate lexical entries, in the same way that we all store singulars.
• The problem is not, of course, confined to plurals. The past tense, the passive voice, various word-order rules, suffixes, word combination rules and all the laws of English we each so unconsciously know give SLI people difficulty too.
• When Gopnik first published these findings after studying the English family she was immediately and fiercely attacked.
•Gopnik hypothesises that people with SLI store English plurals in their minds as separate lexical entries, in the same way that we all store singulars.
• The problem is not, of course, confined to plurals. The past tense, the passive voice, various word-order rules, suffixes, word combination rules and all the laws of English we each so unconsciously know give SLI people difficulty too.
• When Gopnik first published these findings after studying the English family she was immediately and fiercely attacked.
•SLI people have more trouble picking out the subtler sounds of speech from the stream of louder sounds.
• This lends credence to the view that the speech and hearing parts of the brain are next door to the grammar parts, and both are damaged by SLI.
• SLI results from damage to the brain caused in the third trimester of pregnancy by an unusual version of a gene on chromosome 7.
• When ancestral human beings first evolved a language instinct, it grew in the region devoted to sound production and processing.
• A genetic lesion in that part ofthe brain therefore affects grammatical ability, speech and hearing – all three modules.
The ‘evolutionary’ in evolutionary psychology refers to the concept of adaptation, which is the process by which complex organs (like the brain) reverse-engineer to discern what they are designed to do.
• Pinker contends that the same applies to the human brain – its modules are most probably designed for particular functions.
• There is a particular historical irony here: The concept of design in nature was once one of the strongest arguments against evolution. Darwin’s genius was to use the argument from design just as explicitly but in service of the opposite conclusion – that natural selection can account for complex adaptation.
• So successfully has Darwin’s hypothesis been supported that complex adaptation is now considered primary evidence that natural selection has been at work.
One example of a complex adaptation is language instinct, which is easy to conceive as being advantageous to our ancestors in Africa for clear and sophisticated communication between themselves and others about survival needs (e.g., avoiding areas that lions had been spotted in).
•Evolutionary psychology is a new discipline that has brought sweeping new insights to the study of human behaviour in many fields.
• Behaviour genetics seeks variation between individuals and seeks to link that variation to genes.
• Evolutionary psychology seeks common human behaviour and assumes no individual differences exist.
• The disagreement between these two approaches may be exaggerated. One studies the genetics of common, universal, species-specific features while the other studies the genetics of individual differences.
• Both are a sort of truth. All human beings have a language instinct, whereas all monkeys do not, but that instinct does not develop equally well in all people.
• The conclusions of both behaviour genetics and evolutionary psychology remain distinctly unpalatable to many non-scientists, whose main objection is a superficially reasonable argument from incredulity.