Gould & Lewontin (1979)

Adaptation & Natural Selection “I am convinced that natural selection

has been the main, but not the exclusive means of modification” (Darwin)

What exactly does ‘main means’ entail? • Is 51% of modification due to natural selection? • Is 98% of modification due to natural selection?

What traits or behaviours should be considered as adaptations?

Sociobiology & Evolutionary Psychology

E. O. Wilson, Sociobiology: The new synthesis, 1975

Evolution of social behaviours, humans and non-humans

“adaptationist programme”• Identify trait/behaviour under selection• Determine how that trait/behaviour may have adaptive

value (environment of evolutionary adaptedness)• Determine ‘trade-offs’ for sub-optimal traits (best

compromise) Panglossian

Criticism “It’s all in our genes”: biological determinism

• A Natural History of Rape

“Evolutionary psychologists believe that the belly-button is an adaptation for storing small berries on the long trek back to camp.” (Kurzban, 2002)

Gould & Lewontin warn of going too far with adaptationist thinking

Are both sides fighting ‘straw men’?

Spandrels “spaces left over” Architectural

constraint By-product is then

exapted for current purpose (mosaics)

Corbels & Squinches BUT… were

spandrels really the only option?

Dennett argues that squinches or corbels can also be used for dome ceilings

San Marco was designed to display mosiacs.

If not natural selection… No adaptation and no selection

• E.g. genetic drift, change due to chance No adaptation and no selection on specific trait

• Selection on some other trait drives form of trait De-couple adaptation and selection

• i.e. one or the other, but not both Multiple adaptations and selection, no selective

bias Exaption, spandrels

With so many interactions, trait-by-trait analysis isn’t ideal; look at the whole

How far is too far?Gould warned of the “dangers and fallacies” (Gould 1997, p. 10750) of over-attributing adaptive functions to traits that might not be adaptations, but the real danger is to fail to consider functional hypotheses. Tonsils often become infected and therefore are (or were) frequently removed by surgery. Which scientific response do you prefer?: (1) Mock any suggestion that tonsils might serve an important function by loudly insisting that not all traits have adaptive functions; or (2) generate and test as many functional hypotheses as you can think of to make sure that by removing the tonsils no lasting harm is done to the patient?

• Hagen, Controversies surrounding evolutionary psychology

Wynne (2007)

Does anthropomorphism belong in Science?

History: no, yes, no,?? Modern anthropomorphism:

• Critical anthropomorphism/theromorphism Put yourself in the place of the animal, but as

the animal• Biocentric anthropomorphism

Bekoff, study of animal emotions

Burden of Proof If we agree animals likely do have

emotions, should the burden of proof be shared?

Is saying “there’s no way to tell” really just a cop-out?• What about intra-species comparisons?

Semantics• Episodic-like memory, personality-like

characteristics, remorseful-like behaviour?

“the difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind”• Darwin, The Descent of Man

Group Question Do you think human emotions are

adaptations or spandrels? What implications, if any, would your

answer have on the use of anthropomorphism in science?

Discussion Questions At what point are you taking adaptationist thinking

too far? When can you safely call a trait a spandrel? Where should the burden of proof lie in terms of

animal emotions? Proving they exist, or proving they don’t exist?

Is anthropomorphism merely a semantics problem? Do you agree that the difference between animal and

human minds is one of “degree, and not of kind”? How do you define ‘animal intelligence’? Is our

definition too anthropomorphic or anthropocentric? Should we focus on how well adapted animals are, instead of how ‘intelligent’ they are?