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Week 2- Psych xx3 evolution(textbook notes).docx

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McMaster University
Joe Kim

Chapter 2: Evolutionary Psychology (Textbook) Introduction: • Evolutionary psychology is the pursuit of psychology science with explicit attention to contemporary knowledge and theory about the evolutionary process Ex. Claus Wedekind and his collaborates conducted an experiment, where male students were recruited to be “odour donors”. The men were given fragrance-free soap to shower with, and clean T-shirts, which they were instructed to wear for two consecutive nights. Agroup of female students then were given the zip-locked bags containing the t-shirts and were instructed to sniff the contents. The odours were rated in respect to their intensity and the pleasantness. Naturally cycling women (those not taking “the pill”), rated odours of men who were genetically dissimilar to themselves as significantly more pleasant than the odours of men genetically similar to them. The c hypothesis of this experiment was based on the evolved functions (or purpose) of women’s reactions to male odour. The first idea is that woman’s choice of a mate is influenced by her affective response to male odours. The second is that there is a potential cost associated with being attracted to an individual with a similar MHC genotype. The third is that taking oral contraceptives puts women in an infertile psychophysiological state. Essential Facts and Ideas about Evolution • There are many indications that populations of organisms change over generations, in other words they evolve. Such indications include: fossil records, phylogenetic trees(can be constructed based on anatomical similarities of embryo or similarities between DNAsequences (including sequence of non-transcribed ‘neutral’DNA) • Major evolutionary changes occur over long periods of time , sometimes thousands of years, often it is assumed that the study of evolution is purely inferential and therefore direct empirical observation is inaccessible • Many evolutionary process can be directly observed and used to support evolution since rapid changes also occur – sometimes over several generations, through a lifetime, or even over the course of a year • Additive microevilutation= big evolutionary changes The Theory of Evolution by Natural Selection • The first evidence of natural selection came from Darwin’s observation of the differences and changes in physical characteristics and behaviours of the finches across the environments of the Galapagos islands • Individuals of any given species differ, and some of the ways in which they differ may affect their survival and reproduction , through heritability of traits Useful c traits are selected and allow for reproduction and survival and through this propagate themselves into the future • Natural selection is a stabilizing process- changes occur when necessary Why Evolutionary Theory Matters to Psychological Design Adaptions • Natural selection also alters behaviour • Adaptions :many traits of organisms, both physiological and psychological serve specific functions that benefited their bearers over generations by increasing their reproductive success, or fitness Ex. Daphnia water flea, and their phototactic behaviour used to avoid predators Functionality • Adaptions are economic and efficient, but their purposes, especially when it comes to psychology are much harder to identify • The functions of adaptions tend to be inferred from their operations and corresponding hypotheses that have been empirically tested • An individual’s current traits exist because they have been inherited from ancestors with better reproductive success –better genes lead to greater chances of survival and reproduction • Adaptions are not always advantageous as the environment is always changing- they are not perfect but they are optimal for the environment developed in Sexual Selection • Sexual selection and the resulting differential reproduction is a special form of natural selection based on competition to mate and reproduced • The study of mate choice within intersexual selection is the underlying psychological mechanisms that guide attraction and mating • Attraction is a factor of the sex of individuals: their gamete
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