Evolution and Evolution and Human NatureHuman Nature

From Sociobiology to From Sociobiology to Evolutionary Evolutionary PsychologyPsychology

13.1 1975 and All That13.1 1975 and All That

In 1975, E. O. Wilson published In 1975, E. O. Wilson published Sociobiology: The New SynthesisSociobiology: The New Synthesis

ended with an attempt to apply ended with an attempt to apply adaptionist reasoning to human adaptionist reasoning to human behaviorbehavior

What are the difficulties of that What are the difficulties of that enterprise?enterprise?

1. Humans are not very adequate as 1. Humans are not very adequate as experimental animals because:experimental animals because: long-livedlong-lived expensive to keep in captivityexpensive to keep in captivity ethical concernsethical concerns

2. Most of our immediate relatives are 2. Most of our immediate relatives are extinctextinct Evolutionary hypotheses about our Evolutionary hypotheses about our

psychological and social traits are hard psychological and social traits are hard to test by the comparative methodto test by the comparative method

3. Humans now live in environments that 3. Humans now live in environments that differ from the environments in which differ from the environments in which we evolvedwe evolved foodfood artificial lightartificial light

Tow consequences:Tow consequences:

3.1 Its risky to assume adaptive stability 3.1 Its risky to assume adaptive stability over significant environmental changeover significant environmental change

inference from current utility to inference from current utility to evolutionary cause is very uncertain if evolutionary cause is very uncertain if the environment has changed in the environment has changed in important ways because a behavior can important ways because a behavior can evolve for one reason and can be evolve for one reason and can be adaptive now for anotheradaptive now for another

Zoos and botanic gardensZoos and botanic gardens

3.2 Its risky to assume phenotypic stability3.2 Its risky to assume phenotypic stability environmental change can change environmental change can change

developmental outcomesdevelopmental outcomes f. e. European populations are generally f. e. European populations are generally

much taller today than 100 years ago, much taller today than 100 years ago, because they eat betterbecause they eat better

4. What is the appropriate grain of 4. What is the appropriate grain of analysis?analysis? Adaptionist conceptions could over- or Adaptionist conceptions could over- or

underestimate the extent to which different underestimate the extent to which different properties of an organism form a linked properties of an organism form a linked evolutionary systemevolutionary system

5. Adaptation and devolopment: distinct 5. Adaptation and devolopment: distinct issuesissues

you can´t use the one to infer the otheryou can´t use the one to infer the other Adaptation does not mean that there is Adaptation does not mean that there is

developmental stability because often developmental stability because often input is neededinput is needed that constitutes facultative traitsthat constitutes facultative traits

Developmental stability does not mean Developmental stability does not mean that there is an adaptationthat there is an adaptation Insensitivity to environmental factors may Insensitivity to environmental factors may

be the result from the developmental be the result from the developmental system itself or from adaptive evolution system itself or from adaptive evolution buffering against environmental buffering against environmental disturbancedisturbance

Genetic diseases: insensitive to Genetic diseases: insensitive to environmental change, but no adaptationenvironmental change, but no adaptation

13.2 The Wilson Program13.2 The Wilson Program

based on the idea that some human based on the idea that some human behavoirs are adaptationsbehavoirs are adaptations

populations differ in behavioral populations differ in behavioral profiles that are heritableprofiles that are heritable

they can be facultative/ conditional or they can be facultative/ conditional or obligate/ unconditionalobligate/ unconditional

f. e. incest aviodance, male sexual f. e. incest aviodance, male sexual promiscuity, femal coyness, promiscuity, femal coyness, infanticide, rape, hostility to infanticide, rape, hostility to strangersstrangers

evolutionary histories reconstructed evolutionary histories reconstructed from behavioral traits are similar to from behavioral traits are similar to those reconstructed from those reconstructed from morphological and genetic onesmorphological and genetic ones

sex role differentiation based on the sex role differentiation based on the fact that:fact that:

males don´t bear the cost of lactation males don´t bear the cost of lactation and pregnancy and sperm is and pregnancy and sperm is metabolically cheaper than eggsmetabolically cheaper than eggs

gender differentiation in mating gender differentiation in mating decisions and in parental care decisionsdecisions and in parental care decisions

f. e. males are more promiscuous and f. e. males are more promiscuous and females engage more in parental carefemales engage more in parental care

this pattern of explanation might not this pattern of explanation might not work with humans because,work with humans because,

1.1. Human sexual relations have functions Human sexual relations have functions additional to fertilizationadditional to fertilization

2.2. femal sexual behavior might be a primate femal sexual behavior might be a primate inheritance rather than a specific human inheritance rather than a specific human adaptation > nonselective explanationsadaptation > nonselective explanations

human behavioral repertoire is not an human behavioral repertoire is not an aggregation of independent unitsaggregation of independent units

there are connected traits opposed to there are connected traits opposed to mosaic traitsmosaic traits

behaviors might just be alterable by behaviors might just be alterable by altering the underlying mental altering the underlying mental mechanisms that are used for many mechanisms that are used for many different purposesdifferent purposes

13.3 From Darwinian 13.3 From Darwinian Behaviorism to Darwinian Behaviorism to Darwinian

PsychologyPsychology realization that the psychological realization that the psychological

mechanisms that generate behavior are the mechanisms that generate behavior are the proper focus of evolutionary theorizingproper focus of evolutionary theorizing

biological anthropology as intermediate part biological anthropology as intermediate part of this transition, represented by Richard of this transition, represented by Richard Alexander:Alexander:

Many behaviors are novel and learned on the Many behaviors are novel and learned on the spot in response to unusual circumstancesspot in response to unusual circumstances

behavior is genuinely diverse and is the behavior is genuinely diverse and is the manifestation of a naturally selected manifestation of a naturally selected learning rulelearning rule

f. e. in the avunculate social system f. e. in the avunculate social system where a man gives his resources to his where a man gives his resources to his sisters´ children rather than his wife´s sisters´ children rather than his wife´s children because:children because:

there is lowered confidence in paternitythere is lowered confidence in paternity happens when society forces wives and happens when society forces wives and

husbands to live seperatelyhusbands to live seperately four criticisms of this example and the four criticisms of this example and the

general program it represents:general program it represents:1. grain problem:1. grain problem: Sociological factors and the general Sociological factors and the general

human motivation to avoid punishment human motivation to avoid punishment are sufficient to explain human are sufficient to explain human behavior in the avunculate societiesbehavior in the avunculate societies

its not necessary to postulate a learning rule its not necessary to postulate a learning rule to choose the best reproductive strategy for to choose the best reproductive strategy for the circumstancesthe circumstances

2. its hard to measure fitness benefits2. its hard to measure fitness benefits f. e. economic resources don´t correlate f. e. economic resources don´t correlate

with biological fitnesswith biological fitness

3. even if fitness benefits are measurable: 3. even if fitness benefits are measurable: what are the possible alternative what are the possible alternative behaviors?behaviors?

4. a correlation of behavior and inclusive 4. a correlation of behavior and inclusive fitness is not important when the fitness is not important when the proximal mechanisms are missing that proximal mechanisms are missing that produce that behavior produce that behavior

precise data about the correlation of precise data about the correlation of resource distribution behavior and resource distribution behavior and inclusive fitness are not to be inclusive fitness are not to be expectedexpected

when disconfirming data (drug when disconfirming data (drug abuse, celibacy) are mere accidents abuse, celibacy) are mere accidents then the successes could be mere then the successes could be mere accidents, tooaccidents, too

13.4 Evolutionary 13.4 Evolutionary Psychology and Its PromisePsychology and Its Promise

there are huge differences among human culturesthere are huge differences among human cultures in genetics within group differences are greater in genetics within group differences are greater

than between group differences and in the than between group differences and in the cultural realm its the reversecultural realm its the reverse

social sciences want to explain the between group social sciences want to explain the between group differences with differences in cultural resourcesdifferences with differences in cultural resources

Evolutionary psychologists (sociobiology´s latest Evolutionary psychologists (sociobiology´s latest defenders) are against the division between defenders) are against the division between evolutionary and cultural theory becauseevolutionary and cultural theory because

1. human cultural diversity is less intense than it 1. human cultural diversity is less intense than it appearsappears

2. diversity itself may have an evolutionary 2. diversity itself may have an evolutionary explanationexplanation

f. e. Noam Chomsky´s „language f. e. Noam Chomsky´s „language acquisition device“:acquisition device“: Humanly possible languages are Humanly possible languages are

restricted by the domain-specific restricted by the domain-specific cognitive structurecognitive structure

This device has „switches“ which explain This device has „switches“ which explain the differences in languagethe differences in language

ergo: diversity is less than it appears and ergo: diversity is less than it appears and can be explained by a single mechanismcan be explained by a single mechanism

also: inappropriateness of a nature/ also: inappropriateness of a nature/ culture dichotomyculture dichotomy if language is a specific adaptation it if language is a specific adaptation it

must have been co-evolved with culturemust have been co-evolved with culture

evolutionary psychologists claim a evolutionary psychologists claim a modular theory of mind which are modular theory of mind which are Darwinian algorithmsDarwinian algorithms

module is to be understood in the module is to be understood in the sense of Jerry Fodorsense of Jerry Fodor

they are: domain-specific, mandatory, they are: domain-specific, mandatory, opaque and informationally encapsulatedopaque and informationally encapsulated

the task is to find Darwinian algorithms the task is to find Darwinian algorithms by the strategy of adaptive thinking:by the strategy of adaptive thinking:

infer the adaptation from the infer the adaptation from the ecological contextecological context

1. identify the adaptive problems our 1. identify the adaptive problems our ancestors confrontedancestors confronted

2. figure out the correlation between 2. figure out the correlation between aspects of the environment they need to aspects of the environment they need to know and are able to know (cues)know and are able to know (cues)

3. construct an information-processing 3. construct an information-processing design that could solve the adaptive design that could solve the adaptive problem using the available cues and problem using the available cues and evaluate possible designs using the evaluate possible designs using the techniques of optimality modelingtechniques of optimality modeling

4. experimentally test for the existence of 4. experimentally test for the existence of the hypothesized mechanismthe hypothesized mechanism

13.5 Evolutionary 13.5 Evolutionary Psychology and Its Psychology and Its

ProblemsProblems there are two problems of the standard there are two problems of the standard

formulation of evolutionary psychologyformulation of evolutionary psychology1. there is no invariant environment to which the 1. there is no invariant environment to which the

lineage can be adapted tolineage can be adapted to the social environment and the lineage change the social environment and the lineage change

togethertogether

2. modules are vulnerable to exploitation in a 2. modules are vulnerable to exploitation in a malign worldmalign world

language: a rigid module couldn´t evolve language: a rigid module couldn´t evolve because it wouldn´t be exploited since because it wouldn´t be exploited since individuals want to understand each other in individuals want to understand each other in the first placethe first place an arms race in the evolution of language would an arms race in the evolution of language would

require a non-modulare language acquisition devicerequire a non-modulare language acquisition device

our cognitive skills are too complicated, our cognitive skills are too complicated, and there is too little input from the and there is too little input from the environment, for their development to environment, for their development to be the result of a general learning be the result of a general learning mechanismmechanism

poverty of the stimulus argumentpoverty of the stimulus argument 3 objections to this point:3 objections to this point:1. even superior performance in a certain 1. even superior performance in a certain

cognitive area is not sufficient to claim cognitive area is not sufficient to claim a Darwinian algorithma Darwinian algorithm

f. e. chess and car driving are domain-f. e. chess and car driving are domain-specific and widely spread through the specific and widely spread through the population but they cannot be based on population but they cannot be based on a Darwinian algorithma Darwinian algorithm

2. the poverty of the stimulus argument 2. the poverty of the stimulus argument does not support some of the central does not support some of the central hypotheses of evolutionary psychologyhypotheses of evolutionary psychology

f. e. Cosmides and Tooby claim that f. e. Cosmides and Tooby claim that we have a module of social exchangewe have a module of social exchange

their reasoning is the inverse of their reasoning is the inverse of poverty of the stimulus reasoningpoverty of the stimulus reasoning

f. e. Wason card selection task is f. e. Wason card selection task is computationally easy but we need the computationally easy but we need the right inputright input

3. many important problems cannot be 3. many important problems cannot be solved by a modular mechanism solved by a modular mechanism

f. e. the pragmatics of language cannot f. e. the pragmatics of language cannot be handled by a specialist device be handled by a specialist device because because everything everything the hearer knows is the hearer knows is important to decode the speakers intentimportant to decode the speakers intent

these two problems are linked because:these two problems are linked because: the adaptive problem is always being the adaptive problem is always being

transformed in an arms race and transformed in an arms race and hardwired mechanisms are vulnerable hardwired mechanisms are vulnerable to deception in such a fierce worldto deception in such a fierce world

Cognitive adaptation often transforms Cognitive adaptation often transforms the environment rather than being an the environment rather than being an accomodation to itaccomodation to it

so the methodology of discovering the so the methodology of discovering the mechanisms by first trying to discover mechanisms by first trying to discover the problems is not adequate the problems is not adequate

it overlooks the interactive character of it overlooks the interactive character of social evolutionsocial evolution

the problem culminates if population the problem culminates if population structure plays a role in human structure plays a role in human evolution becauseevolution because

1. population structure is clearly not a 1. population structure is clearly not a stable background against which stable background against which psychology changespsychology changes

2. there are different adaptions to expect 2. there are different adaptions to expect f. e. many altruistic behaviors could evolve f. e. many altruistic behaviors could evolve

in a structured population what would in a structured population what would otherwise not be the caseotherwise not be the case

13.6 Memes and Cultural 13.6 Memes and Cultural EvolutionEvolution

cultural life itself can be seen as an cultural life itself can be seen as an autonomous evolutionary processautonomous evolutionary process

in Dawkins´s language, ideas are in Dawkins´s language, ideas are memes that ought to show phenotypic memes that ought to show phenotypic variation, differential fitness, and variation, differential fitness, and heritabilityheritability

3 reasons against this concept:3 reasons against this concept:

1. there may be no thing as cumulative 1. there may be no thing as cumulative selection in the cultural realmselection in the cultural realm

2. there is no active designer in natural 2. there is no active designer in natural selection but there is one in cultural selection but there is one in cultural evolutionevolution

an exception could be the domain of an exception could be the domain of science with the growth of objective science with the growth of objective knowledge over timeknowledge over time

3. in the explanatory idea „survival of 3. in the explanatory idea „survival of the fittest“ fittest means expected the fittest“ fittest means expected reproductive success, but there is no reproductive success, but there is no explanation of the nature of the explanation of the nature of the fitness of ideas (with the possible fitness of ideas (with the possible exception of scientific ideas)exception of scientific ideas)