Presentation on theme: "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."— Presentation transcript:
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?
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
Its 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?
spaces left over Architectural constraint By-product is then exapted for current purpose (mosaics)
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.
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 isnt ideal; look at the whole
Gould warned of the dangers and fallacies (Gould 1997, p ) 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
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
If we agree animals likely do have emotions, should the burden of proof be shared? Is saying theres 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
Do you think human emotions are adaptations or spandrels? What implications, if any, would your answer have on the use of anthropomorphism in science?
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 dont 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?