PSY101 - Chapter 4: Nature, Nurture, and Human Diversity Flashcards
Behavioral Genetics
The study of effects of environmental and genetic factors, and their interplay, on differences in psychological traits.
Genes
Small segments of DNA molecules.
DNA strands connect in double helixes which make up chromosomes.
Every cell in the human body contains 23 chromosomes donated by the mother and 23 donated by the father.
Identical vs. Fraternal Twins
Identical Twins develop from a single fertilized egg, are genetically identical and may only be the same sex.
Fraternal Twins develop from separate fertilized eggs and share half their genes, like normal siblings and may be of different sexes.
Molecular Genetics
To identify specific genes that influence normal human traits such as body weight, sexual orientation, and basic personality traits.
Heritability (h²)
A mathematical estimate of the extent to which variation among individuals can be attributed to their differing genes.
– Personality (40-50%), IQ heritability increases with age (22% at age 2, 54-62% at 75+), Schizophrenia (80%), Major Depression (40%).
Group Differences
(e.g. Between men and women) Are not considered heritable.
Natural Selection
Organisms’ varied offspring compete for survival. Certain behavioral characteristics increase odds of survival in a particular environment. Offspring that survive reproduce and pass on their genes.
Evolutionary Psychologists
Believe our tendencies as humans have been shaped by evolution. For example, some women’s experience of nausea in the first three months of pregnancy predisposes them to avoid foods that may be toxic to the fetus.
Female Reproductive Strategies
Can produce fewer children over limited time span.
- Seek males who have resources to protect them + offspring.
- Evaluate males on basis of earning capacity, ambition, industry, status, maturity.
- Attracted to male love acts that display resources.
- -> seek men who are older.
- -> more threatened by emotional infidelity.
Male Reproductive Strategies
Can conceive from puberty until death; lots of potential offspring.
- Seek females who can reproduce.
- Evaluate females on basis of youth, health, beauty.
- Attracted to female love acts that signal reproductive capabilities.
- -> seek women who are younger.
- -> more threatened by sexual infidelity.
Environment Impact on Brain Development
Enriched environments yield larger thicker cortexes than impoverished environments.
Individualist Cultures
Self as independent - emphasizes the virtues of independence, autonomy, and self-reliance, people strive for personal achievement.
Collectivist Cultures
Self as interdependent - emphasizes the virtues of interdependence, cooperation, and social harmony, people derive more satisfaction from the status of the valued group.
Nature and Nurture
Work together to cause traits. A trait may exist in a person, but be caused to grow by the environment.
Epigenetics
The study of molecular mechanisms by which environments trigger genetic expression.