Evolution and Human Nature

1. Evolution and Human Nature From Sociobiology to Evolutionary Psychology

2. 13.1 1975 and All That • In 1975, E. O. Wilson published Sociobiology: The New Synthesis • ended with an attempt to apply adaptionist reasoning to human behavior • What are the difficulties of that enterprise?

3. 1. Humans are not very adequate as experimental animals because: • long-lived • expensive to keep in captivity • ethical concerns 2. Most of our immediate relatives are extinct • Evolutionary hypotheses about our psychological and social traits are hard to test by the comparative method

4. 3. Humans now live in environments that differ from the environments in which we evolved • food • artificial light Tow consequences: 3.1 Its risky to assume adaptive stability over significant environmental change • inference from current utility to evolutionary cause is very uncertain if the environment has changed in important ways because a behavior can evolve for one reason and can be adaptive now for another

5. Zoos and botanic gardens 3.2 Its risky to assume phenotypic stability • environmental change can change developmental outcomes • f. e. European populations are generally much taller today than 100 years ago, because they eat better 4. What is the appropriate grain of analysis? • Adaptionist conceptions could over- or underestimate the extent to which different properties of an organism form a linked evolutionary system

6. 5. Adaptation and devolopment: distinct issues • you can´t use the one to infer the other • Adaptation does not mean that there is developmental stability because often input is needed • that constitutes facultative traits • Developmental stability does not mean that there is an adaptation • Insensitivity to environmental factors may be the result from the developmental system itself or from adaptive evolution buffering against environmental disturbance • Genetic diseases: insensitive to environmental change, but no adaptation

7. 13.2 The Wilson Program • based on the idea that some human behavoirs are adaptations • populations differ in behavioral profiles that are heritable • they can be facultative/ conditional or obligate/ unconditional • f. e. incest aviodance, male sexual promiscuity, femal coyness, infanticide, rape, hostility to strangers

8. evolutionary histories reconstructed from behavioral traits are similar to those reconstructed from morphological and genetic ones • sex role differentiation based on the fact that: • males don´t bear the cost of lactation and pregnancy and sperm is metabolically cheaper than eggs • gender differentiation in mating decisions and in parental care decisions • f. e. males are more promiscuous and females engage more in parental care

9. this pattern of explanation might not work with humans because, • Human sexual relations have functions additional to fertilization • femal sexual behavior might be a primate inheritance rather than a specific human adaptation > nonselective explanations • human behavioral repertoire is not an aggregation of independent units • there are connected traits opposed to mosaic traits • behaviors might just be alterable by altering the underlying mental mechanisms that are used for many different purposes

10. 13.3 From Darwinian Behaviorism to Darwinian Psychology • realization that the psychological mechanisms that generate behavior are the proper focus of evolutionary theorizing • biological anthropology as intermediate part of this transition, represented by Richard Alexander: • Many behaviors are novel and learned on the spot in response to unusual circumstances • behavior is genuinely diverse and is the manifestation of a naturally selected learning rule

11. f. e. in the avunculate social system where a man gives his resources to his sisters´ children rather than his wife´s children because: • there is lowered confidence in paternity • happens when society forces wives and husbands to live seperately • four criticisms of this example and the general program it represents: 1. grain problem: • Sociological factors and the general human motivation to avoid punishment are sufficient to explain human behavior in the avunculate societies

12. its not necessary to postulate a learning rule to choose the best reproductive strategy for the circumstances 2. its hard to measure fitness benefits • f. e. economic resources don´t correlate with biological fitness 3. even if fitness benefits are measurable: what are the possible alternative behaviors? 4. a correlation of behavior and inclusive fitness is not important when the proximal mechanisms are missing that produce that behavior

13. precise data about the correlation of resource distribution behavior and inclusive fitness are not to be expected • when disconfirming data (drug abuse, celibacy) are mere accidents then the successes could be mere accidents, too

14. 13.4 Evolutionary Psychology and Its Promise • there are huge differences among human cultures • in genetics within group differences are greater than between group differences and in the cultural realm its the reverse • social sciences want to explain the between group differences with differences in cultural resources • Evolutionary psychologists (sociobiology´s latest defenders) are against the division between evolutionary and cultural theory because 1. human cultural diversity is less intense than it appears 2. diversity itself may have an evolutionary explanation

15. f. e. Noam Chomsky´s „language acquisition device“: • Humanly possible languages are restricted by the domain-specific cognitive structure • This device has „switches“ which explain the differences in language • ergo: diversity is less than it appears and can be explained by a single mechanism • also: inappropriateness of a nature/ culture dichotomy • if language is a specific adaptation it must have been co-evolved with culture

16. evolutionary psychologists claim a modular theory of mind which are Darwinian algorithms • module is to be understood in the sense of Jerry Fodor • they are: domain-specific, mandatory, opaque and informationally encapsulated • the task is to find Darwinian algorithms by the strategy of adaptive thinking: • infer the adaptation from the ecological context 1. identify the adaptive problems our ancestors confronted

17. 2. figure out the correlation between aspects of the environment they need to know and are able to know (cues) 3. construct an information-processing design that could solve the adaptive problem using the available cues and evaluate possible designs using the techniques of optimality modeling 4. experimentally test for the existence of the hypothesized mechanism

18. 13.5 Evolutionary Psychology and Its Problems • there are two problems of the standard formulation of evolutionary psychology 1. there is no invariant environment to which the lineage can be adapted to • the social environment and the lineage change together 2. modules are vulnerable to exploitation in a malign world • language: a rigid module couldn´t evolve because it wouldn´t be exploited since individuals want to understand each other in the first place • an arms race in the evolution of language would require a non-modulare language acquisition device

19. our cognitive skills are too complicated, and there is too little input from the environment, for their development to be the result of a general learning mechanism • poverty of the stimulus argument • 3 objections to this point: 1. even superior performance in a certain cognitive area is not sufficient to claim a Darwinian algorithm • f. e. chess and car driving are domain-specific and widely spread through the population but they cannot be based on a Darwinian algorithm

20. 2. the poverty of the stimulus argument does not support some of the central hypotheses of evolutionary psychology • f. e. Cosmides and Tooby claim that we have a module of social exchange • their reasoning is the inverse of poverty of the stimulus reasoning • f. e. Wason card selection task is computationally easy but we need the right input 3. many important problems cannot be solved by a modular mechanism

21. f. e. the pragmatics of language cannot be handled by a specialist device because everything the hearer knows is important to decode the speakers intent • these two problems are linked because: • the adaptive problem is always being transformed in an arms race and hardwired mechanisms are vulnerable to deception in such a fierce world • Cognitive adaptation often transforms the environment rather than being an accomodation to it

22. so the methodology of discovering the mechanisms by first trying to discover the problems is not adequate • it overlooks the interactive character of social evolution • the problem culminates if population structure plays a role in human evolution because 1. population structure is clearly not a stable background against which psychology changes 2. there are different adaptions to expect • f. e. many altruistic behaviors could evolve in a structured population what would otherwise not be the case

23. 13.6 Memes and Cultural Evolution • cultural life itself can be seen as an autonomous evolutionary process • in Dawkins´s language, ideas are memes that ought to show phenotypic variation, differential fitness, and heritability • 3 reasons against this concept: 1. there may be no thing as cumulative selection in the cultural realm

24. 2. there is no active designer in natural selection but there is one in cultural evolution • an exception could be the domain of science with the growth of objective knowledge over time 3. in the explanatory idea „survival of the fittest“ fittest means expected reproductive success, but there is no explanation of the nature of the fitness of ideas (with the possible exception of scientific ideas)