Chapter Eight Flashcards
natural selection
results in the gradual changes in a species over time, as successful variants increase in frequency and eventually spread throughout the gene pool, replacing the less successful variants
sexual selection
- the evolution of characteristics based on their mating benefits
- two kinds intrasexual vs intersexual competition
intrasexual competition
competition between same sex individuals for mates, resources, etc.
intersexual selection
members of one sex choosing a mate based on their preferences for particular qualities
differential gene reproduction
defined by reproductive success relative to others
inclusive fitness theory
- the “inclusive” part refers to the fact that the characteristics that facilitate reproduction need not affect the personal production of offspring
- they can affect the survival and reproduction of genetic relatives as well
adaptations
reliably developing structure in the organism which causes the solution to an adaptive problem
byproducts of adaptation
things created by the evolutionary process that are not adaptations
(lightbulbs designed to produce light which is its function but it also produces heat as an incidental by product)
evolutionary noise
random variants that are neutral with respect to selection
(ie. the design of a lightbulb, there are minor variations in the surface texture of the bulb that do not affect the functioning of the design elements)
basic human motivation proposed to have evolved to prevent us from being excluded
- according to hogan, being ostracized from a group would have been extremely damaging
- therefore, it can be predicted that humans have evolved psychological mechanisms to prevent being excluded
evidence indicating that the need to belong is a central motive for humans
- baumeister and leary argue that the group serves several key adaptive functions for individuals:
- share food, information, and other resources
- offer protection from external threat or defence from rival groups
- contain concentrations of mates, needed for reproduction
- contain kin, which provide opportunities to receive altruism and invest in genetic relatives
genetics and altruism
- burnstein and colleagues hypothesized that helping others is a direct function of the recipients’ ability to enhance the inclusive fitness of the helpers
evidence of genetics and altruism
- studies in the US and japan support predictions
- participants asked to imagine different individuals sleeping in different rooms of a burning house; tendency to help is a direct function of the degree of relatedness
age and altruism
burnstein and colleagues predicted that people should help younger relatives more than older relatives because helping older kin would have less impact, on average, on their reproductive success than would helping a younger person
research on age and altruism
- studies on famine and disease, relationship between age and helping support this
- participants asked to imagine themselves in a sub-saharan african country that suffered from famine, infants were helped less, 10 year olds helped more then after 75 years old helped less
three perspectives on study of emotions
- examine wether facial expressions of emotion are interpreted in the same ways across cultures, on the assumption that universality is one criterion for adaptation
- emotions are adaptive psychological mechanisms that signal various “fitness accordances” in the social environment
- manipulation hypothesis: suggest that emotions are designed to exploit the psychological mechanisms of others
ekman’s study on the cross-cultural universality of emotions and facial expressions
- assembled pictures of several different faces showing one of 7 emotions (happiness, disgust, anger, fear, surprise, sadness and contempt)
- a bunch of countries showed universal agreement
sexual selection and sex differences in aggression
females will express great care in their choice of mates, and males will be forced to compete for access = aggression
effective polygny and sex difference in aggression
among males, a few males will father multiple offspring, whereass some will have none at all, which is what is known as effective polygny
intrasexual competition and sex differences in aggression
- male strategies have been characterized by risky intrasexual competition for females or for the social status and resources that attract females
- males are victims of aggression more than females because they are in competition primarily with other males
why men and women should differ in jealousy
- concern for females is wether a mate’s behaviour puts her at risk for losing his resources, time and commitment
- males are predicted to become more jealous in response to sexual infidelity, while females are predicted to become more jealous in response to cues to long-term diversion of a mate’s commitment, such as emotional involvement with someone else
when a hypothetical forced questionnaire (imagining your partner forming a deep connection with someone else vs having passionate sexual intercourse) onto undergraduates
- males were more distressed when imagining their partners having intercourse with someone else
- females contrasted this, having been more distressed when imagining their partners becoming emotionally involved with someone else
why men and women differ in their mate preferences
- because females bare the burdens of the heavy obligatory parental investment, they are predicted to place more value on a potential mate’s financial resources and the qualities that lead to such resources
- males predicted to place greater value on a female’s physical appearance, which provides cues to her fertility
how individual differences may be due to environmental differences acting on species-typical mechanisms
- triggers specific sexual strategies in individuals
- develop expectations that parental resources will not be reliably or predictably provided
frequency-dependent selection
causes the frequency of men and women to remain roughly equal
limitations evolutionary psychology
- adaptations are forged over the long expanse of thousands or millions of generations, and we cannot go back in time and determine with absolute certainty what the precise selective forces on humans have been
- just scratched the surface of understanding the nature, details, and design features of evolved psychological adaptations
- modern conditions are undoubtedly different from ancestral conditions in many respects, so that what was adaptive in the past might not be adaptive in the present
- it is sometimes easy to come up with different and competing evolutionary hypotheses for the same phenomena
- sometimes been accused of being untestable and hence unfalsifiable
