week 4: epigenetics

Adaptation

Behavioral patterns or traits that developed because they helped ancestors survive and reproduce.

Sociometer Theory (Leary)

Self-esteem is an internal gauge that monitors the degree to which we are accepted vs. rejected by others.

Evolutionary Role of Shame

Shame is an adaptive emotion that motivates us to avoid behavior that would lead to social exclusion/rejection.

Life History Strategy

The trade-off between Slow-LH (investing in long-term survival/stable parenting) and Fast-LH (early reproduction in dangerous/unstable environments).

Environmental Triggers

Some behavior patterns only activate in response to certain environments (e.g., being extra aggressive only if you grew up in a dangerous neighborhood).

Choosing different paths

People may have different "evolved strategies" but choose the one that fits their specific strengths (e.g., a physically strong person using aggression, a smaller person using charm).

Frequency-Dependent Selection

Some traits only work if they are rare. Example: Being a "cheater" (psychopath) only works if most people are "trusting." If everyone cheated, the strategy would fail.

3 ways to explain individual differences

Environmental Triggers, Choosing different paths, Frequency-Dependent Selection

5 Stress Tests

Criticisms of Evol. Psych: Methodology, Reproductive Instinct, Conservative Bias, Human Flexibility, Social Structure

Methodology

We can't travel back in time to prove these stories; it's mostly "just-so" storytelling.

Reproductive Instinct

Many people choose NOT to have kids (contraception), which contradicts a "pure" reproductive drive.

Conservative Bias

It implies that because things were a certain way (e.g., gender roles), they should stay that way.

Human Flexibility

Humans are much more flexible and less "hard-wired" than other animals

Social Structure

Many behaviors are caused by current social rules/economies, not ancient genes.

Behavioral Genetics

Research focused on how much of the variation in personality is due to genetics vs. environment.

The "Twin Rule"

Identical (MZ) twins share 100% of genes; Fraternal (DZ) twins and siblings share 50% of genes.

Heritability Coefficient (h²)

The formula: (rMz - rDz) x 2. It calculates the percentage of variance in a trait that is due to genes.

Probabilistic Nudges

Genes do not "force" behavior; they provide "nudges" or predispositions that make certain behaviors more likely.

Genetic Confounding

When an environmental effect is actually caused by genes (e.g., a "nurturing" home environment might be caused by the parents' "agreeable" genes, which they also passed to the child).

Molecular Genetics

The study of whether specific genes (like DRD4 for Dopamine/Sensation-seeking or 5-HTT for Serotonin/Anxiety) correlate with traits.

GWAS

Genome-Wide Association Studies; looking at hundreds of thousands of genes at once in giant samples.

Gene-Environment Interaction

The idea that genes aren't "set in stone"—their effect depends on the environment (e.g., a "tall" gene only works if the child has enough food).

Epigenetics

Non-genetic influences (like stress or nutrition) that change how or whether a gene is expressed without changing the DNA itself.

Biology: Cause & Effect

Personality is "Both/And." Biology causes behavior, but environment/experience also changes your biological state (e.g., stress changes your cortisol).