Evolution and Psychology

1. Psychology BSc – General Foundations Module Evolution and Psychology Dr Stephen Walker January 11, 2007

2. Aims and Objectives • Aims: These two lectures aim to refresh students’ knowledge of the theory of evolution, or to introduce them to it, and to introduce them to aspects of psychology which have been influenced by evolutionary approaches. • Objectives: By the end of the lectures the students should: • know the general outlines of the theory of evolution and the time course of human evolution

3. Objectives continued • be able to answer correctly a majority of the questions on the self-assessment test included in the handout • understand some of the key differences between nativist and empiricist theories in psychology • be aware of the sections of the course text (Gleitman, 1999/2004) where evolutionary approaches are applied to perceptual, cognitive, emotional and social aspects of psychology.

4. Topics to be covered • The theory of evolution • What Darwinians say about psychological topics • Schools of thought influenced by Darwinian approaches • Areas of psychology that have been or could be influenced by these approaches

5. Format of lectures • There will be a very brief coverage of a large number of areas • The question addressed is a general one: what is the relevance of evolution for psychological topics? • The answer to be given is in terms of the ‘nature/nurture’ issue.

6. Topic and essay question “Does the theory of evolution have any relevance for psychological topics?” • Gleitman’s textbook mentions evolution, or evolutionary theorists, or “biological bases” in several places. • So to that extent evolution must be relevant for psychological topics, although —

7. Culture vs. Evolution • Gleitman et al. (1999, page 436) agree that it is arguable that human social behaviour is “so thoroughly infused by culture” that comparisons with the Darwinian influences on animal behaviour are fruitless. • “…there is no question that human social behavior is flexible and subject to cultural learning in ways that other species’ behaviour is not….. (Gleitman et al, 2004; p. 458)

8. Basic Reading see p. 1 of handout

9. Topics to be covered • I will look first at the analysis of instinctive behaviour in animals (ethology) • Then I will cover theoretical arguments about assuming innate capacities in human psychology (Pinker, 1984, 2003) • In the second lecture I will briefly outline the time course of human evolution (not in Gleitman) • — and also review the material in the textbook which supports the existence of innate biases in the perceptual, cognitive and emotional worlds of human infants

10. Darwin in Gleitman et al. 1999p. 406&2004p. 416 All Darwin’s publications are freely available online at http://darwin-online.org.uk

11. The Theory of Evolution • Resources are not unlimited • Some individuals will flourish more than others and produce more offspring • There are inherited differences between individuals, with some random changes • Natural selection occurs if a population changes over generations because of this (see e.g. Dawkins, 1995)

12. Evolution — II • The first point about evolution is that it connects the human species with the rest of the animal kingdom, • However, it is also possible and indeed likely that the course of human evolution has led to humans being uniquely different from all other currently living species

13. Common pattern for body plans: standard biology texts

14. EVOLUTIONARILY CONSERVED MOLECULAR GENETIC MECHANISMS FOR PATTERNING THE EMBRYONIC BRAIN. Reichert & Simeone (2001) Fly mutant restored with human gene Fly mutant restored with mouse gene Mouse mutant restored with fly gene

15. What Darwinians say about Psychological topics • Darwinians emphasise innate or “built-in” factors in psychology • They tend to emphasise nature rather than nurture and are “nativists” rather than “empiricists” • They are often interested in development during an individual’s life-span

16. Darwinian Schools of Thought(p 2 of handout) • Ethology: scientific study of innate factors in animal behaviour (N. Tinbergen and K. Lorenz, Nobel Prize, 1973) • Sociobiology: as above, but emphasis on social behaviour (E.O. Wilson, 1975) • Evolutionary Psychology: emphasis on the effects of human evolution on human psychology (Tooby and Cosmides, 1992; Pinker, 1994, 1998, 2002/3)

17. Pause before weaver bird next Examples of natural selection in animal behaviour − instincts or “genetically determined behaviour patterns” I am going to look very briefly at animal behaviour. It is clearly not contentious to give evolutionary explanations for animal behaviour, but such explanations are not always completely obvious. But for questions such as “why do birds build nests?” there is not a problem.

18. Gleitman, 1999, p. 407.Weaverbird nest:“Many (?) animals have genetically determined behavior patterns characteristic of their species.” Gleitman, 2004, p.418. Bowerbird nest. “..natural selection will lead to an evolution of how animals behave..” (p. 417)

19. Ethological analyses of animal behaviour

20. Pecking 1

21. “Supernormal Stimulus” Gleitman, 1999 p.409 1995, p. 382 Not in Gleitman et al. 2004

22. Supernormal stimulus defined

23. Supernormal stimuli Fig 3.8 in Manning and Dawkings (1992) p. 52

24. Supernormal stimuli − 2

25. Supernormal stimuli − 3 Morrison, D. S., & Petticrew, M. (2004). Deep and crisp and eaten: Scotland's deep-fried Mars bar. Lancet, 364(9452), 2180-2180. (not on list) We did a telephone survey in June, 2004, of random selection of the 627 fish and chip shops in Scotland …….. 66 shops sold deep-fried Mars bars …….we did also find some evidence of the penetrance of the Mediterranean diet into Scotland, …. albeit in the form of deep- fried pizza

26. More animal behaviour in Gleitman et al.

27. Lorenz walking Gleitman et al (2004) page 508

28. Built-in social behaviour p. 408, 1999 not in 2004

29. Gleitman, 1995, p. 400 1999, p. 427 Parental feeding 11. 6 Innate triggers In many species, the parents’ care-taking behaviors are elicited by specific signals from the young. (Gleitman, 2004; p. 430)

30. Cuckoos Gleitman, 1995, p. 400 1999, p. 427 Not in 2004 Mentioned by Darwin (1859)

31. Cuckoos − one of Darwin’s examples

32. Evolutionary Psychology • Darwinian theory helps explain the behaviour of cuckoos, and almost all other animal species, but does it explain human behaviour in the same way? • One example follows of an evolutionary prediction for human behaviour which turns out to be wrong.

33. Kenrick et al, 2003Psychological Review, 110(1), 3-28 “At the most general level, evolutionary psychology can be defined as the study of cognitive, affective, and behavioral mechanisms as the solutions to recurrent adaptive problems.” “Along with the morphological features designed by natural selection, organisms also inherit central nervous systems……The behavioural inclinations of a bat would not work well in the body of a dolphin or giraffe and vice-versa.”

35. Kenrick et al. wrong • over a period of 35 years in Sweden (1965-1999), there was no overall over-representation of stepchildren as victims. • (Temrin, Nordlund, & Sterner, 2004) • In families with both stepchildren and children genetically related to the offender, genetic children tended to be more likely to be victims.

36. Animal psychology has been most influenced (ethology & sociobiology) Psychologists interested in human language and perception now point to innate mechanisms (Pinker, 1994) Social psychologists appeal to cultural influences and are generally against innate factors (Harre, 1986) Areas of psychology influenced- see top of p. 3 and p. 6 of handout

37. Review of innate influence in areas of human psychology (p3 on handout) • Perceptual systems: vision; colour vision (olfaction: 2004 Nobel). Also motor systems, and eye-hand co-ordination. • Cognitive systems: built-in concepts of time, space and physical reality; the bioprogram for 1st language learning • Emotionality: facial expressions as displays • Social systems: bioprograms for social interaction? (Tomasello et al, 1993)

38. Social systems: extra comments (p3) • human intelligence may have evolved because of its importance in social interaction, especially to cope with social exchange rules (Gleitman et al., 1999; p. 494 | 2004; p. 440) • natural inclinations are not necessarily desirable: cultural systems may have often developed to supplant them (Hobbes, 1651; Gleitman, 1999, p. 405 & p. 437; Gleitman, 2004, p. 612)

39. Thomas Hobbes (1651)picture in Gleitman, 1999; p. 406 |text in 2004 edn p. 612

40. pause • The next slide is 2x2 on page 7 • Hobbes is useful as an example of syaing that the “state of nature is not where we are now, but nativists would say he was wrong about the original human state being solitary even though stone age life was probable more brutal and short in general than it is now

41. 2 x 2 (page 7 of handout)

42. Cover Pinker (1994, 1998, 2003) − an example of an evolutionary psychologist

43. Pinker, S. (1994) The Language Instinct. pp 419-20. • “So what are the modules of the human mind?” • “Using biological anthropology, we can look for evidence that a problem is one that our ancestors had to solve in the environments in which they evolved — • so language and face recognition are at least candidates for innate modules, but reading and driving are not.”

44. Genes and Language: • Psycholinguists such as Noam Chomsky and Steven Pinker have been convinced since the 1960’s that the human capacity for language capacity is innate. • In the last six years, particular genes involved with language capacity have been discovered. (Not covered in Gleitman et al.)

45. Genes and Language: BBC October 01

46. Pinker comments October 2001

47. From the Wellcome Trust web pages

48. National Geographic

49. Mice 05 foxp2

50. Nature 2002 • Language is a uniquely human trait likely to have been a prerequisite for the development of human culture. The ability to develop articulate speech relies on capabilities, such as fine control of the larynx and mouth, that are absent in chimpanzees and other great apes. FOXP2 is the first gene relevant to the human ability to develop language. A point mutation in FOXP2 co-segregates with a disorder in a family in which half of the members have severe articulation difficulties accompanied by linguistic and grammatical impairment. This gene is disrupted by translocation in an unrelated individual who has a similar disorder. Thus, two functional copies of FOXP2 seem to be required for acquisition of normal spoken language. We sequenced the complementary DNAs that encode the FOXP2 protein in the chimpanzee, gorilla, orang-utan, rhesus macaque and mouse, and compared them with the human cDNA. We also investigated intraspecific variation of the human FOXP2 gene. Here we show that human FOXP2 contains changes in amino-acid coding and a pattern of nucleotide polymorphism, which strongly suggest that this gene has been the target of selection during recent human evolution.