Origins of Personality: Genetics, Biology, and Evolution

Flashcards covering the origins of personality from genetics, twin studies, brain structures, neurotransmitters, and evolutionary psychology based on the lecture notes.

Genetics

DNA inherited from biological parents at the moment of conception.

Environment

Every experience post-conception.

Shared Environments

Factors that siblings share, such as parents and home life.

Non-Shared Environment

Experiences unique to the individual, such as friends, teachers, and personal injuries.

Monozygotic Twins

Twins who share $100\%$ of DNA, often used for studying differences between DNA and environment.

Personality variance findings

$50\%$ of variance in personality traits is attributable to DNA, while shared environment has virtually zero influence.

Restriction of Range

A limitation of twin research where most twins are adopted into similar, stable, middle-class homes, underestimating diverse environments.

Confounding variables

Variables in research that are not accounted for.

Selection

A gene-environment interaction where individuals seek out environments that suit their traits.

Evocation

A gene-environment interaction where a child's personality influences how parents or others treat them.

Genotype

Genetic predisposition.

Phenotype

Physical expression of genotype.

Epigenetics

Gene expression changes caused by the environment where the change is in expression, not actual DNA.

Intergenerational Effects

Changes where trauma can lead to epigenetic changes that are passed down.

Reactivity

Biological difference where introverts are more reactive to stimuli than extraverts.

Frontal lobe

Brain structure responsible for self-regulation, planning, and emotion management; damage leads to lower conscientiousness.

Amygdala

Processes fear and reactions to stimuli; reacts strongly for those high in neuroticism and shows sensitivity to positive emotions in extroverts.

Ventral Striatum

The brain's reward center, where high activity is linked to low conscientiousness and impulsivity.

Dopamine

Neurotransmitter linked to risk-taking, impulsivity, and high openness to experience when present in high levels.

Serotonin

Neurotransmitter where high levels are correlated with lower impulsivity and higher self-control.

Larks

Morning people who tend to be higher in conscientiousness and agreeableness.

Owls

Evening people who tend to be higher in extraversion and openness to experience.

Selfish Gene Theory

Evolutionary theory that we are more likely to help those who share our genes and the youngest who have the highest reproductive potential.

The need to Belong

A nearly universal human trait to want to belong; historically, being excluded meant death.

Sociosexuality

Attitudes toward sex without commitment; men typically have more desire for this than women.

Maintenance of variation

The concept that different personality traits are beneficial in different environments.

Fertility shifts

Changes during high-fertility days where women may show increased attraction to masculine traits and men find their scent and voices more attractive.

Testosterone

Hormone linked to aggression and dominance.

Estrogen

Hormone linked to a power motive and the desire to control and influence others.

Cortisol

Stress hormone that shows how underlying personality traits influence the endocrine system, such as a rise in cortisol following a competitive loss for those high in power motive.