Behavior Genetics, Nature, Nurture, and Human Diversity

Flashcards based on lecture notes covering behavior genetics, nature and nurture, twin studies, heritability, environmental influences, and culture.

What is the definition of behavior genetics?

Behavior genetics is the study of how heredity and environment contribute to human differences.

How are genes defined in relation to DNA and chromosomes?

Genes are segments or parts of DNA molecules, which are found in chromosomes inside the nuclei of cells.

What is a chromosome?

A chromosome is a threadlike structure made largely of DNA molecules.

What is DNA?

DNA is a spiraling, complex molecule containing genes.

What is a genome?

A genome is an organism's entire collection of genes.

What is the structural hierarchy from cell to gene?

Cell -> nucleus -> chromosome -> DNA -> gene.

How are chromosomes inherited in humans?

Humans inherit 46 chromosomes in 23 pairs, with 23 coming from the mother's egg and 23 from the father's sperm.

How many genes do humans have in their genome, and what states can they exist in?

Humans have 20,000-25,000 genes, and these genes can be active or inactive.

What percentage of their genome do humans share with one another?

Humans share 99.9% of their genome, meaning even tiny genetic differences can be important.

How does the human genome compare to that of chimpanzees and bananas?

About 0.5-4% difference separates humans from chimpanzees, and about 50% of our genome is banana-like.

How do identical twins form, and how much inherited DNA do they share?

Identical twins form from 1 egg + 1 sperm and share essentially 100% of their inherited DNA.

How do semi-identical twins form, and what percentage of DNA do they share?

Semi-identical twins form from 1 egg + 2 sperm and share about 75% of their DNA.

How do fraternal twins form, and what percentage of DNA do they share on average?

Fraternal twins form from 2 eggs + 2 sperm and share about 50% of their DNA on average.

How do identical twins compare to fraternal twins regarding behavioral and personality similarities?

Identical twins are more alike than fraternal twins, even if they are raised in different homes.

What specific traits and outcomes show strong similarity in identical twins?

Personality traits such as extraversion and neuroticism; behaviors/outcomes such as divorce rate; attitudes, interests, fears, and abilities/IQ scores.

What is the risk of developing Alzheimer's disease if an identical twin vs. a fraternal twin has it?

If one identical twin has Alzheimer's, the other twin has a 60% risk; in fraternal twins, the risk is 30%.

What is molecular genetics and what can it help us see?

Molecular genetics is the study of the molecular structure and function of genes, which may help us see exactly how specific genes influence behavior.

What can genetic tests currently reveal and potentially identify in the future?

Genetic tests can reveal which people are at risk for many physical diseases and may eventually identify people at risk for mental health disorders.

What role does environment play in mental disorders compared to specific genes?

When it comes to mental disorders, environment, the people you're around, and your experiences may play a bigger role than specific genes.

How does natural selection shape traits within a population?

Conditions make it harder for individuals with certain traits/genes to survive and reproduce, so certain traits and genes are selected and spread through the population.

How stable is temperament from infancy into adulthood?

From infancy into adulthood, most people do not seem to change temperament.

What are the three types of temperament and their characteristics?

Easy (cheerful/predictable), difficult (irritable/unpredictable), and slow to warm up (resists new people/situations).

What is heritability?

Heritability is how much of the differences in a trait between people can be explained by genetics.

If 90% of differences in height are explained by genes, does that mean an individual's height is 90% genetic?

No, 90% of differences in height between people being explained by genes does not mean 90% of a specific person's height is genetic.

What is a gene x environment interaction?

It means nature and nurture work together: some traits are set more by genes, while other traits develop in response to our experiences.

What is meant by a bidirectional system between genes and environment?

Genes can influence our environment and behavior, while our environment and experiences can also influence us; it goes both ways and basically feeds itself.

How can culture interact with traits that appear genetic?

Something that looks genetic may actually be influenced by culture/environment, such as different diet and exercise beliefs affecting health.

What areas of life can parenting influence despite strong genetic effects on personality?

Parenting can influence values, beliefs, manners, attitudes, and politics.

How do parent influences differ from peer influences?

Parents have more influence on things like education, responsibility, religion, and interacting with authority, while peers have more influence on popularity, habits, music/recreation, and clothing/culture.

What is the definition of culture in psychology?

Culture consists of patterns of ideas, attitudes, values, lifestyle habits, and traditions shared by a group and passed on to future generations.

What are cultural norms, and how do fast cultural changes demonstrate non-genetic influence?

Cultural norms are acceptable and expected behaviors; culture can change over time, and these changes happen too fast to be genetic.

What is the difference between individualism and collectivism?

Individualism values independence and personal goals, while collectivism values interdependence and group goals.

How is gender defined in these notes?

Gender refers to the physical, social, and behavioral characteristics culturally associated with male and female roles.