“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
“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 (1979) 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.
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
Comparative cognition is: A comparison of mental abilities of species Cognitive abilities and capacities e.g. capacities: Alex the Grey ParrotAlex the Grey Parrot
Why is animal behaviour studied in psych department, not zoology? 4 main reasons: Uniqueness Control & irreversible effects Simplicity & generality Continuity
Certain animals have unique properties that allow us to study subjects which could not be studied any other way: Mice and genes Giant Squid Axons High pecking rates of pigeons Echolocation in bats Absolute pitch in songbirds
For practical and ethical reasons, we can have greater control in animals over both: Genes Environments Irreversible Effects: Drugs, lesions, gene manipulations
Insights from Model Systems Mendel studied peas Impact on study of schizophrenia Generality of principles Building blocks of cognition
Neurobiological continuity e.g. Hippocampal lesions in mice and men Evolutionary continuity Divergent and convergent evolution Analagous vs homologous traits
How is information acquired or learned? How is information processed? How is information retained?
Types of Studies 4 approaches to studying animal behaviour: Naturalistic Observation (Ethological) Field Experiments Behavioural Experiments Behavioural Neuroscience (Physiological)
Named for ethologist Niko Tinbergen Proximate (How) vs Ultimate (Why)
Causation: Brain – e.g. Broca’s area Hormones – e.g. Testosterone stimulates aggressive behaviour Pheremones – e.g. Spatial behaviour, tracking Development or Ontogeny Nature/Nurture – genes and environment Critical periods – e.g. language or imprinting
Function or Adaptation How has an organism evolved for survival? e.g. Birds fly south for warmth & food e.g. Mammal nurture young Phylogeny Evolutionary explanations, other than adaptation e.g. Genetic drift