10. Evolution & Personality

Evolutionary Theory

The process by which distinctive features of human nature (physical and psychological) have developed over many generations due to selective advantage.

Natural Selection

The process by which organisms with mechanisms and adaptations that help with survival or reproduction leave more offspring, resulting in evolutionary change.

Theory of natural selection

– Members of the species must differ on some characteristics

– Some of these variations must be heritable (i.e., genetic)

– Organisms with “successful variants” leave more offspring because those attributes help with survival or reproduction.

Assumes hostile forces of nature

Hostile forces of nature

Any event that impedes survival

Examples: food shortages, diseases, parasites, predators, & extreme weather

Sexual Selection

The process by which certain heritable characteristics give selective mating benefits to individuals, leading to differential gene reproduction.

Intrasexual Competition

Competition between members of the same sex for mating access.

The winner has characteristics that contribute to reproductive success.

Intersexual Competition

One sex chooses mates based on their preference for particular qualities.

Inclusive Fitness Theory

The ability of an individual to transmit genes that facilitate reproduction and survival to the next generation, including genes shared with relatives.

Adaptations

Characteristics that exist due to natural or sexual selection because they helped solve problems of survival or reproduction.

By-products

Characteristics that do not solve adaptive problems and do not have functional design.

Evolutionary Noise

Random variations that are neutral with respect to selection.

Deductive reasoning approach

“Top down,” theory-driven method

Start with a theory or idea of how something works and test it

Inductive reasoning approach

“Bottom up,” data-driven method

See something, then develop a hypothesis to help explain it

Need to Belong

The evolved need for humans to live in groups, leading to social anxiety when individuals are shunned by a group.

Altruism

The belief in or practice of disinterested and selfless concern for the well-being of others, often driven by inclusive fitness and genetic relatedness.

Parental Investment Theory

The theory that in species where females invest more heavily in offspring than males do, they are more selective of their mates, making men more competitive with each other for mates due to this limitation.

Sexual Dimorphism Hypothesis

The hypothesis that the sexual selection process leads to a gradual change in species over many generations, causing differences in reproductive strategies and physical characteristics.

Sex differences of evolutionary theory

–       Aggression: Males will fight each other for mates. In almost every category (except verbal), men are more aggressive than women.

–       Jealousy

–       Mate Preferences

Young Male Syndrome

The tendency of young men to engage in risky forms of aggression due to evolutionary factors, such as the need to display physical prowess, deter and gain status.

Frequency-dependent selection

The selection of certain individual differences based on their frequency in a population.

Limitations of Evolutionary Approach

–  No physical evidence of mechanisms

– Limitations of current knowledge

– Easy to come up with alternative explanations for hypotheses

– Hypotheses untestable/can’t be falsified