Evolution, Genetics, and Experience: Thinking about the Biology of Behavior

Question 1

What is epigenetics

Answer 1

the study of inheritance other than mechanisms related to the coding in the DNA
- the modern way to evaluate the role of genes and environment on behavior (the interaction between nature and nurture)

Question 2

Ethology

Answer 2

• Focused on instinctive behaviors.
• Strong genetic basis, no time for learning

Question 3

Cartesian Dualism

Answer 3

physical, scientific

Question 4

Behaviorism

Answer 4

All behavior is learned

Question 5

Evidence against the nature-nature dichotomy

Answer 5

1. complex behaviors are affected by brain damage
   2.Many non-human species exhibit complex abilities that are supposedly purely psychological (human)

Question 6

Description of the biology of behavior

Answer 6

genes and experience do not combine additively
There exists a set of circumstances in which any specific behavior will occur despite one’s genetic or experiential background

Question 7

Individuals vs. Populations

Answer 7

Gene x Environment interactions are inseparable when considering the development of individuals

Question 8

Individuals vs. Populations

Answer 8

The effects of genes and environment ARE separable when considering differences among individuals within a population

Question 9

Behavioral genetics

Answer 9

the study of the genetic and environmental influences on behavior in a population
- assumes causes of behavior can be grouped into 2 broad categories (genes or environment)

Question 10

Heritability estimate (h2)

Answer 10

the proportion of variability in a particular trait due to genetic variation

Question 11

Heritability

Answer 11

The proportion of variability in a population that can be attributed to genetic factors

Question 12

Comparisons in twin studies

Answer 12

1. Identical (MZ) twins, raised together
   - Genetically identical
   - Family environment identical
   - Any differences between these individuals must be due to unique environmental influences (ENS)
2. Identical (MZ) twins, raised apart
   - genetically identical
   - family environment different
   - if these people are more similar than 2 unrelated people, similarities must be due to genetic factors (h2)
3. MZ twins raised together with MZ twins raised apart
   - same degree of genetic similarity
   - one pair shares family environment, the other doesn’t
   - if twins raised together are more similar than twins raised apart, must be due to shared environmental influences

Question 13

3 major conclusions

Answer 13

1. 40% < h2 < 70%
   when looking at population level, about half of the variability in that population is due to genetic factors
   doesn’t mean
   - a single gene is responsible
   - the path from genes to behavior is simple
   - behavior can’t be changed
2. ES < 10%
   - family has an effect, but its not consistent, predictable effect. May be that parents treat children differently (shared environment isn’t similar)
3. ENS around 50%
   - a significant proportion of variability is due to neither genetics nor family