© Kip Smith, 2003 Part 2 Nature Evolution, language, and species-typical (innate) behavior patterns

© Kip Smith, 2003 Outline of the course Foundations The science of mind and behavior Nature How evolution has shaped mind and behavior Species-typical behavior patterns Examples: Sticklebacks Language Later: Nurture, (Ab)Normal minds

© Kip Smith, 2003 Today Evolution, what it is, how it works Random variation, genes Natural selection Sexual selection Its implications for psychology Some of our behavior patterns are innate They have been shaped by millions of years of adaptation to our environmental niche

© Kip Smith, 2003 Next The curious behavior patterns of the stickleback Curious behavior patterns of humans Mate selection Casual sex Jealousy Aggression Altruism

© Kip Smith, 2003 Next + Language, a uniquely human behavior Syntax Semantics Evidence for the innate nature of language & for Chomsky’s generative grammar Children and the emergence of creole The language developed by the deaf children of Nicaragua

© Kip Smith, 2003 Schedule Wenzday Jan 29 Friday Jan 31 Monday Feb 3 Wenzday Feb 5 Friday Feb Evolution 2.2 Curious behavior Muddiest point 2.3 Language Study guide Review Test

© Kip Smith, How evolution has shaped mind and behavior

© Kip Smith, 2003 An Evolution Primer Evolution has three components Random Variation Natural Selection Sexual Selection Your textbook, like most books since Victorian times, discusses only the first two

© Kip Smith, Random variation Variation is the engine of diversity Sexual reproduction & Genetic mutation Produce minute, random genetic differences

© Kip Smith, 2003 Minute, random genetic differences Make you different than your parents Accumulate to make different species

© Kip Smith, 2003 Genes Biochemical units of heredity Segments of chromosomes, of DNA Humans have 46 chromosomes 23 from mother, 23 from father Everything about genes and how they do what they do is more appropriately discussed in biology class.

© Kip Smith, 2003 Minute random changes in genetic code If the variation does not harm or interfere with the organism’s ability to fit its niche, the organism has the opportunity to mate and pass those genes on to the next generation Most variations are not helpful They are unlikely to survive and be passed on Some are monstrous and are spontaneously aborted

© Kip Smith, 2003 Random vs. Directed Evolutionary Has no direction Has no purpose Has no moral status or implications Does not care Evolution happens Teleological change Has a purpose Has a goal Examples Goal-directed behavior Moral training

© Kip Smith, 2003 Evolution is NOT directed The random nature of genetic variation has significant implications that some people find unsettling: We humans are NOT the pinnacle of creation We just happen to be the way we are If the world were to have another go at it, human may not have evolved Bats have a much better claim to the pinnacle than humans They FIT their niche perfectly

© Kip Smith, 2003 Myth 1 “Evolution says that humans are descended from monkeys” Humans, apes, and monkeys have a common ancestor Random variation has made us different than that ancestor and each other

© Kip Smith, Natural selection Natural selection eliminates species that fail to match their niche Natural selection winnows random variations that do not FIT Fitness refers to the organism’s match to its ecological niche Fit = the organism's match to its ecological niche

© Kip Smith, 2003 Fit is the match to a niche If a species fits its niche, it is likely to survive Natural selection and fit IS all about the survival of the survivors It is NOT about the survival of the fittest, the healthiest, the smartest, or the most beautiful

© Kip Smith, 2003 Natural selection works at the species level Utterly impersonal If you don’t fit your niche, you die If your species doesn’t fit its niche, you go extinct Those who survive are likely to breed and pass their genes to the next generation

© Kip Smith, 2003 Nature and evolution are impersonal If your environment changes and your species does not adapt, you go extinct Large dinosaurs Mammoths Whales? Beatles

© Kip Smith, 2003 The role of the environment The environment provides the niche The species has to adapt to it Random variation is the engine of adaptation Natural selection gauges the fit

© Kip Smith, 2003 The human niche The human niche is hunter-gatherer / predatory nomad / prey Humans evolved to solve the problems faced by a predatory species that was easy prey on the Pleistocene African savanna

© Kip Smith, 2003 Our adaptation We evolved as we did to fit the hunter- gatherer niche Bipedal Eyes forward We are social We form groups for protection and the exchange of goods and services

© Kip Smith, 2003 Our adaptation We can eat almost everything Three kinds of teeth We store fat to help us survive lean times We crave salt and sugar We grew big brains Why?

© Kip Smith, 2003 Our quandary We are biologically & genetically prepared for hunting & gathering, for a predatory, nomadic life style We are adapted for a niche that no longer exists We have changed our environment and we don’t fit it

© Kip Smith, Sexual Selection In most mammalian species, including humans, females choose which male they will mate with Males develop sexual displays to attract and retain females The peacock’s tail The stag’s horns …

© Kip Smith, 2003 Sexual displays Are ‘expensive’ Are an indicator of the male’s fitness

© Kip Smith, 2003 Sexual selection works at the individual level The peacock with a fine fine superfine tail is advertising his fitness to all the peahens Every peahen knows it is wiser to mate with a fit peacock than with an unfit peacock

© Kip Smith, 2003 Puritanical censorship Victorian male chauvinist scientists had a real problem with Darwin’s theory of sexual selection Females choosing males? Totally scandalous !

© Kip Smith, 2003 Bi-directional sexual selection Darwin suggested that in some species, including humans, sexual selection works both ways Females choose the males with the best displays Males choose the females with the best displays

© Kip Smith, 2003 For next time Read Scientific American article 1: Timbergen, N. (1952). The curious behavior of the stickleback Chapters 1, 2, 3