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Evolutionary Psychology: Counting Babies or Studying Information Processing Mechanisms Charles Crawford Department of Psychology Simon Fraser University.

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Presentation on theme: "Evolutionary Psychology: Counting Babies or Studying Information Processing Mechanisms Charles Crawford Department of Psychology Simon Fraser University."— Presentation transcript:

1 Evolutionary Psychology: Counting Babies or Studying Information Processing Mechanisms Charles Crawford Department of Psychology Simon Fraser University Burnaby, BC, Canada E-mail: crawford@sfu.ca Website: http://www.sfu.ca/faculty/crawford

2 1,000,000 years

3 Infinitesimal segment of evolutionary time

4 Given the Difference Between Then and Now Can we use the Theory of Evolution by Natural Selection in the study of the limits of human nature? If we can, how can it be done? By the study of adaptations: Then & Now

5 A Central Problem of Humanity How can we set up societies –that are founded on moral principles, and yet –are pliable and comfortable enough for people so that the society will persist? Example: Collapse of the USSR Resolving “naturalistic” and “moralistic” fallacies Is there a role for evolutionary psychology?

6 Outline Adaptations –As anatomical structures,.. –Fitness maximization –Criticisms Adaptations –Information processing mechanisms –Environments and adaptations: Then and Now Validating evolutionary explanations

7 Darwin’s Finches

8 Beaks: Tools For Survival, Growth, and Reproduction

9 E.O. Wilson’s Definition of Adaptation An anatomical structure, a physiological process, or a behavior pattern that makes an organism more fit to survive and reproduce in competition with other members of its species. Examples: –Beaks of finches –Upright walking Note the emphasis on reproduction

10 Beaks and Reproductive Success Many traits contribute to survival and reproduction in different species, including humans. What role for reproduction in the study of adaptations

11 Homicide and Reproductive Success in the Yanammo

12 Implications individuals were selected to behave to maximize their reproductive success adaptations are manifest at the level of behavior innate specialized psychological mechanisms are not required for maximizing fitness therefore, differences between ancestral and current environments are less significant than some claim

13 Criticisms Although adaptations were selected because they maximized ancestral reproductive success, does this mean they act to maximize it now? Is behavior the result of the actions of psychological mechanisms? Can natural selection select for general purpose mechanism? How critical are differences between ancestral and current environments in research?

14 What Do We Need? a more adequate conception of behavioural adaptations methods for studying behaviour producing adaptations

15 Fever as an Adaptation raising body temperature to help the body fight parasitic infections processes information about the invaders and the body’s ability to resist them benefit: destruction of parasites costs: energy requirements, damage to body

16 Male Scorpionfly Mating Tactics: Dead insect Proteinaceous mass Forced copulation

17 Environment ( male-male competition) Low Medium High Mating Tactic Genetically innat e "mental " mechanism Dead insect + courtship Proteinaceous mass + courtship Attempted forced copulation h 2 = 0 Scorpionfly Mating Tactics and Environmental Conditions

18 Adaptation Defined a set of genetically-coded decision processes that enabled ancestral organisms to implement cost- benefit analyses in response to specific sets of environmental contingencies, and that organized the effector processes for dealing with those contingencies so that the allele(s) producing the decision processes were reproduced better than alternate allele(s) examples: fever, recognizing kin, forming social contracts, deceiving oneself,...

19 Environments and Adaptations Innate adaptation Operational adaptation Development environment Immediate environment

20 Innate Adaptation: Adaptation as Design The species typical information encoded in particular gene(s) that direct the development of a phenotype in such a way that the genetically encoded information was passed from generation to generation more effectively than information from alternative gene(s). –Example: Genes for the development of intellectual reasoning ability.

21 Operational Adaptation The phenotype that develops on the basis of genetic information in conjunction with the internal and external environment of the organism during development. –Example: Psychological mechanisms for engaging in intellectual reasoning

22 Developmental Environment Ancestral: Ancestral environmental conditions during development that shape the functioning of the ancestral operational adaptation. –Example: Hunter-gatherer teaching, gossip, and the development of intellectual reasoning Current: Environmental conditions that currently shape the develop of the operational adaptation. –Example: TV, schooling,, gossip, and the development of intellectual reasoning ability

23 Immediate Environment Ancestral: Ancestral conditions that activate the operational adaptation to produce an episode of behaviour. –Example: Reasoning about kinship relations Current: Environmental conditions that currently activate the adaptation. –Example: Doing the GRE

24 Intellectual Reasoning: Then and Now Innate adaptation: Genes for organizing intellectual development Reasoning about particular kinship relationships Old operational adaptation: Psychological processes for reasoning about abstract relationships Newer operational adaptation: Psychological processes for reasoning about abstract relationships The GRE TV, reading, & Formal schooling Gossip, informal Schooling, & story telling

25 Evolutionary Psychology Problems faced by our ancestors –Understanding your tribe’s kinship structure Information processing systems that evolved to help provide a solution –Intellectual reasoning processes Way evolved mechanisms function now –Doing the GRE

26 Adaptation functioning: Then and now Now: Contribution to well being Adaptive- culturally variable Yes No Pseudo pathologies Quasinormal behaviours True pathologies Then: Contribution to fitness

27 True Pathologies Have deleterious consequences for individuals possessing them, irrespective of whether they are living in an ancestral or current environment. Examples: –PKU, brain damage, Korsakokff’s syndrome –Autism –Maternal diabetes, hypertension Malfunction of or cost of adaptation

28 Adaptive-Culturally Variable Behaviours that vary in time & space, but that serve adaptation’s original function. Examples: –Language learned - Swedish, English, Portuguese, Esperanto, etc –Athletic sports - Baseball, cricket, hockey –Co-operation, reciprocity –Cheating, self deception, theft, war,...

29 Pseudopathologies Behaviours that contributed to ancestral fitness, but that are no longer adaptive, ethical, or normal –Excessive male sexual jealousy –Prostitution –Anorexic behaviour –Teenage gangs More will emerge as we move further and further from our ancestral environment.

30 Quasinormal Behaviours Behaviors that would have detracted from ancestral fitness, but that have become culturally acceptable and even encouraged –Adoption of genetically unrelated children. –Innocent until proved guilty. –Recreational sexual behaviour. –True altruism –Equal treatment of women Not result of evolved adaptation to produce them

31 Evolutionary and Non- Evolutionary Explanations Should evolutionary and non-evolutionary explanations be compared when testing evolutionary explanations?

32 Relation of Non-Evolutionary and Evolutionary Explanations Evolutionary Explanations Evolutionary theory not used Warp drive explanations Good non-evolutionary explanations

33 Example: Brother-Sister Incest Avoidance close inbreeding is detrimental to survival and reproduction ancestral individuals avoiding it would have had better lifetime reproductive success hypothesized adaptation: intimate rearing of brothers and sisters attenuates sexual attraction when they are adults

34 How do We Validate Evolutionary Explanations of Human Behaviour ? by modeling ancestral selection processes to determine if the adaptation could have evolved cross cultural studies to determine how the adaptation functions in different environments experimental studies to make causal statements about psychological mechanisms locating the basis of the adaptation in nervous and endocrine systems to give biological credibility

35 Benefits of such a mechanism:Effects of Inbreeding on Mortality Two Japanese Cities

36 Ancestral Fitness Model Could such a mechanism have evolved? Independent variables –genetic relatedness –sex of individuals Dependent variables –lifetime reproductive success males females

37 How the Adaptation Functions in Different Environments Marriage and incest rules in many cultures –rules supporting variety of functions exist –how many of these support hypothesis? Naturalistic experiments in various cultures –kibbutz marriages –sim pau marriages Can causal statements be made? –No

38 Experiments: Random Assignment of Treatments to Subjects Age Intimate Rearing Begins Genetic Relationship Brother- Sister Not Related I nfancy Post adolescence Adult sexual attraction No Yes

39 The Nervous and Endocrine Locations ???????????????? Need not be a specific location for, say, incest avoidance.

40 A Central Problem for Humanity How to set up societies –that are founded on moral principles, and yet –are comfortable enough for people that the society will persist? Balancing ideology and reality Dealing with “naturalistic” and “moralistic” fallacies

41 Preventing Brother-Sister Incest Strict laws with severe penalties? –Apache Indians of the American planes Relaxed, intimate rearing conditions –Tellensi of Africa

42 Darwin’s Wisdom Man with all his noble qualities, with sympathy that feels for the most debased, with benevolence which extends not only to other men but to the humblest of living creatures, with his god-like intellect which has penetrated into the movements and constitution of the solar system -- with all these exalted powers -- still bears in his bodily frame the indelible stamp of his lowly origin. (Charles Darwin, The descent of man, 1871/1898, p. 634.)

43 The Naturalistic Fallacy: “What is, is what ought to be” Women are less sexually aggressive than men, therefore, they ought to be less sexually aggressive. Women are lighter than men, therefore… But are there constraints on what can be changed? –Sexual aggressiveness –Height?

44 The Moralistic Fallacy: “What ought to be, is what is” Women and men ought to have the same sexual agendas, therefore, they do, and if they don’t… Women and men ought to be the same weight, therefore,… Must what “ought to be” exist? Tragedies of history Can evolutionary psychology help with the naturalistic and moralistic fallacies?

45 Ancestral Genetic Variation Variability exhausted Variability not exhausted Development freed from genetic Influences Genetic influences on development Remain Genetic variation remains and affects adaptation’s functioning Genetic variation remains, but is not related to adaptations function Affects of Natural Selection on Genetic Variation Remaining Genetic Influences on Development Selection Acts on Genetic Variation Possible Outcomes when Natural Selection Meets Genetic Variation

46 Wilson on Natural Selection and the Human Mind Camus said that the only serious philosophical question is suicide. That is wrong even in the strict sense intended. The biologist, who is concerned with questions of physiology and evolutionary history, realizes that self-knowledge is constrained and shaped by the emotional control centers in the hypothalamus and limbic system of the brain. These centers flood our consciousness with all the emotions--hate, love, guilt, fear, and others--that are consulted by ethical philosophers who wish to intuit the standards of good and evil. What, we are then compelled to ask, made the hypothalamus and limbic system? They evolved by natural selection. The simple biological statement must be pursued to explain ethics and ethical philosophers, if not epistemology and epistemologists, at all depths. (Edward O. Wilson, 1975)


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