Modules 11 and 12: Behavior Genetics and Evolutionary Psychology

behavior genetics
the study of the relative power and limits of genetic and environmental influences on behavior

the building blocks of heredity and development; they are parts of DNA molecules, which are found in chromosomes in the nuclei of cells

46 chromosomes; 23 donated from mother and 23 from father
how many chromosomes does the human genome include?

an organism’s entire collection of genes

what ability do genes have?
they can direct the assembly of proteins that build the body

the environment, or by other genes
the genetic protein assembly can be turned on and off by what?

the genetic code a person inherits

the observable trait a person shows, resulting in part from his or her inherited genotype
ex: IQ, personality, brown eyes

Gene x Environment (GxE) Interaction
the interacting effects of genetics and the environment on the development of traits and characteristics

Phenylketonuria (PKU)
genetic disease, cannot metabolize protein (phenylalanine), can lead to mental disabilities, but the environment can alter the fate of these individuals

study traits of fraternal vs. identical twins; see if the fraternal vary more than identical
to assess the impact of nature and nurture, how do we examine how genes make a difference within the same environment?

personality traits such as extraversion, behaviors/outcomes such as rate of divorce, and abilities such as overall intelligence test scores
studies of twins in adulthood show that identical twins are more alike than fraternal twins in:
(3 things)

we can study the traits of identical twins as they grow up or if they were raised separately
how do we find out how the same genes express themselves in different environments?

religious beliefs, values, manners, attitudes, politics, and habits
despite the strong impact of genetics on personality, parenting has an influence on:

if parenting has an influence, why are siblings so different?
genetic and environmental differences become amplified as people react to them differently; siblings are raised in slightly different families (older parents, different parenting techniques)

a person’s general level and style of emotional reactivity

easy, difficult, slow to warm up
what are three general types of temperament that appear in infancy?

research findings suggest that temperament differences typically ______.

the amount of variation in the population that is explained by genetic factors

if 5 unrelated people had nearly identical upbringing, but different in a trait such as shyness, then the heritability of this trait for them is close to _____ percent.

evolutionary psychology
the study of how evolutionary principles help explain the origin and function of the human mind, traits, and behaviors

how does natural selection work?
1. begin with a species genome, which contains a variety of versions of genes that shape traits
2. conditions make it difficult for individuals with some traits (some versions of those genes) to survive long enough to reproduce
3. other individuals thus have their traits and genes “selected” to spread in the population

why might natural selection have resulted in greater male promiscuity?
explained by evolutionary psychology; little cost to men to spreading extra genes, but for a women a trait of promiscuity would greatly increase the number of babies and it would have greater survival costs

an evolutionary psychologist would note that snakes are often poisonous so those who more readily learned to fear them were more likely to survive and reproduce
why do people so easily acquire a phobia of snakes?