Inheritance of Personality Flashcards
What is behavioral genetics?
Field of research that studies how the genes can influence broad patterns of behavior.
What are controversies around behavior genetics?
It was founded on eugenics, the belief that humanity could be improved through selective breeding and the concern that research might leas the pubic to think outcomes are fixed.
What is genetic confounding?
Problem of distinguishing a result due to genes or due to environment.
What is the research method for behavioral genetics?
The research method is the utilization of twins, if the trait is influenced by genes, people who are genetic relatives ought to be more similar in that trait. The closed the genetic relationship, the more similar.
What is MZ and DZ twins?
MZ, monozygotic, identical twins 100% related
DZ, dizygotic twins, fraternal twins, 50% related
What does behavioral genetics focus on?
The part of the human genome that varies across the population. It focuses on how people are different.
What is the heritability coefficient?
A statistic that reflects the degree to which variance of the trait in the population is attributed to variance in genes.
What is the equation to calculate variance?
h^2 + c^2 + e^2
where h is heritability, c is shared environment and h is non-shared environment.
What does behavioral genetics tell you? (2)
It tells you that genes matter and it provides a window into non-genetic effects, into the effects of the environment.
Why do twin studies suffer from a restriction of range?
Because families from underprivileged or difficult environments are rarely included.
What are the limitations of heritability calculations?
1- heritability does not solve the nature/nurture debate
2- heritability statistics do not really tell you about the process by which genes affect personality and behavior, e.g. television watching is genetic, but we don’t know why.
What is the field that behavioral genetics have evolved into?
Molecular genetics
What is molecular genetics?
Research that unravels how specific genes influence life outcomes. Moved away from twins studies to dive into the DNA, however is not that simple.
What is the genome-wide association study?
Method that pursues research into many genes and gene patterns in order to understand personality. Difficult, expensive and so many analyses are made, the chance of being a coincidence is big.
What is epigenetics?
Study that explores how early life experiences can determine how or even whether a gene is expressed during development. Genes can be the same, but still result in different people.
Nongenetic influences on a gene’s expression.
How does gene development interact with the environment?
The environment can affect heritability itself, e.g. height and poor nutrition or IQ and stimulation/education.
What is niche picking?
It’s basically the active person-environment transaction but for genetically influenced tendencies.
what is the h in the variance equation?
Heritability, the contribution of genetics to the variation of a trait observed in a population. Can be estimated by comparing similarities between people that related to different degrees.
What are some cautions needed dor heritability?
It’s a population estimate and it does not apply to individuals.
Heritability can be zero for traits with no variance (having a heart)
Cannot be assessed without taking the environment into account
It’s specific to the time and population studied
May fluctuate across the lifespan
What is the c in the variance equation?
Shared environment, effects of environmental factors that make those raised together more similar to each other but it DOES NOT speak to any one specific environmental factors.
what is the e variable in the variance equation?
Non-shared environment, captures the effects of environmental factors that make those raised together more DISSIMILAR to each other. Also captures random measurement error.
What are the most heritable traits of the Big 5?
Extraversion and agreeableness, followed by openness.
What is the least heritable trait of the Big 5?
Neuroticism
Why is c’s impact so small?
It’s mostly based on adults and S-data, although c is more prominent in childhood and larger when collected by I-data.
Studies include primarily functional families, restricting the range of variance we are estimated.
Objective x effective environment
What is objective and what is effective environment?
Objective environment: actual, measurable environmental conditions that individuals experience.
Effective environment: how the objective environment actually affects the individual’s trait or behavior.
An environment can be objectively share but effectively non-shared.
What can’t heritability tell you?
Can’t resolve the nature-nurture debate
how/which genes affect personality
What are some potential problems with twin studies?
Selection bias: more similar twins are more likely to reunite, twins that choose to participate are closer, availability heuristics all limit the range.
How similar/different rlly were the environments?
Genes in identical twins might not be identical or the structure in the womb might have been different
Genetic influences may be multiplicative, thus there would be higher results in twin studies than sibling and cousin studies.
What are the gene-environment transactions?
People experience certain environments due to their genetic makeup.
Passive- parents provide both genes AND a caring environment
Evocative- genetic predisposition shape environment and responses from others
Active- seeking out environments in line with genetic predisposition
What is meant by “twin studies are not just for twins”?
It’s meant that is a model, a research paradigm for how we understand genetic environmental influences on development in the population at large.
