PSYO3280 Evolutionary Perspectives

Human Nature

Collection of adaptations that defines us as human

Natural Selection

Process by which adaptations are created and changes take place over time

Adaptations

Inherited solutions to survival and reproductive problems posed by hostile forces of nature

Two forms of seuxal selection

(1) Intrasexual and (2) Intersexual

Intrasexual Competition

Members of the same sex compete with each other for sexual access to members of the other sex

Intersexual Competition

Members of one sex choose a mate based on their preferences for particular qualities in that mate

Differential gene reproduction

Reproductive success relative to others

Inclusive fitness theory

Personal productive success + effects you have on the reproduction of your genetic relatives weighted by genetic relatedness

Products of the Evolutionary Process

(1) Adaptations, (2) Byproducts of adaptations, (3) Noise/random variation

Adaptations

Primary products of selection, causes the solution to an adaptive problem

Special design; efficiency, precision, reliability

Ex: xenophobia, behavioural immune system

Byproducts of adaptations

Incidental effects of adaptations not properly considered to be adaptations

Ex: whiteness of bone is a byproduct of calcium in bones

Noise/Random variation

Neutral with respect to selection

Ex: shape of human earlobe

Adaptive problem

Anything that impedes survival or reproduction

Premises of Evolutionary Psych

(1) Domain-specificity, (2) Numerousness, (3) Functionality

Domain-specificity

Adaptations are designed by evolutionary process to solve specialized adaptive problems

Numerousness

Expectation that there are many adaptations because different adaptations are required to solve different adaptive problems

Functionality

Adaptations are designed to accomplish particular adaptive goals

Deductive reasoning approach

Top Down, theory-driven method

Think: deduct theo down

Inductive reasoning approach

Bottom Up, data-driven method

Think: Im up, inducing data

Level of Human Nature

The Need to Belong, Helping and Altruism, and Universal Emotions

Evolutionary Sex Differences

Similar except in domains where sexes faced different adaptive problems

Examples of Evolutionary Sex Differences

Aggression, Jealousy, Sexual Variety, and Mate Preferences

Most challenging level of analysis

Individual differences (environmental triggers, heritable individual, frequency-dependent)

Reactively heritable

Secondary consequence of heritable body build - enters a man’s decision of whether to pursue an aggressive strategy

Big Five Evolutionary Perspective

Clusters of key features of “adaptive landscapes” of other people

Difference-detecting mechanisms

Designed to notice and remember individual differences that have more relevance for solving social adaptive problems

Limitations of Evolutionary Psych

Cannot go back and determine precise selective forces, modern conditions are different (validity), untestable/unfalsifiable hypotheses

Evolved Mechanisms

Mechanisms evolved to solve particular adaptive problems; promote survival and reproductive success

Ex: sexual jealous helps men solve uncertainty of paternity

Carver et al (2008) - homicides and mating

Coincides with prime ages for mating and most killing come from conflicts over face and status

Griskevicius et al (2015) - relationships

Humans are sensitive to loss of status and rank; Relationship type and associated evolutionary opportunities and threats

Sperm Competition

# of sperm contained in man’s ejaculation varies based on sperm competition risk

Schmitt et al (2004) - mate poaching

More money = more access to sexual resources in short term; Higher SES linked with more success in mate poaching

Sexual Strategies Theory

Men and women have evolved different mating strategies for long and short term mating.

Women look for signs of status, maturity, and resources

Men look for signs of fertility and reproductive value

Nedelec and Beaver (2014) - health and attractiveness

Attractive people tend to have fewer health problems - particularly with depression, asthma, and high blood pressure

Schmitt et al (2004) - characteristics and cheating

Higher conscientiousness associated with lower infidelity; Higher extraversion associated with higher promiscuity

Schmitt et al (2004) - consenting to sex

Mean likelihood of consenting to sex after knowing someone for 1 month; women want to delay occurrence of sex while men would like to accelerate it

Buss (2006) - agreeing to sex

After 5 years of friendship, women and men are equal in agreeing to sex

Regan et al (2006) - thinking about sex

Women: 9 times a week

Men: 37 times a week

Lippa (2009) - sex drive differences

Men have higher sex drive on average than women

Parental Investment Theory

Women incur greater cost to have offspring, meaning they have higher parental investment than men

Good Finanical Prospect

On average, much more important to women and fairly standard across regions

Mate Poaching

Trying to attract someone who is already in a romantic relationship

Short-term: one-night stand

Long-term: engage in a relationship

Most people have tried and been poached!!

Feminist Identity and Mate Poaching

Sex differences in occurrence of short-term mate poaching tends to be smaller in regions with greater gender equality

Sex Differences in Frequent Mate Poaching

Men: extraverted, erotophilic disposition, negative relationship exclusivity

Women: negative agreeableness, erotophilic disposition, negative relationship exclusivity

Sex Differences in Successful Mate Poaching

Men: openness, sexual attractiveness, negative sexual restraint

Women: sexual attractiveness, negative sexual restraint, erotophilic disposition