Behavioral Genetics

Question 0

What are traits?

Answer 0

• Features of living things.
• Physical Traits (eye color)
• Psychological Traits (intelligence)
• Genetic vs. Environmental contribution.

Question 1

What are genes?

Answer 1

• The study of genes and how they predict traits.
• Genes: a molecular unit of heredity of a living organism.

Genome: a genetic code for making a human being.

Question 2

What is the heritability index?

Answer 2

Statistically quantifies the extent to which variation BETWEEN INDIVIDUALS on a trait is due to variation in the genes those individuals carry.

A heritability of 1 indicates that ALL VARIATION in the trait in question is genetic in origin and a heritability of 0 indicates that NONE OF THE VARIATION IS GENETIC.

Question 3

What are twin studies and what do they do?

What are adoption studies and what do they do?

Answer 3

Twin: Can compare correlations between MZ and DZ twins; Comparisons based on equal-environments assumptions.

Adoption: Can compare correlations between biologically related and biologically unrelated members.

Question 4

What happens if a trait is influenced by only genes?

Answer 4

MZ twins (raised together or apart) would correlate to 1.00; DZ twins and other siblings (raised together or apart) would correlate to .50; Adoptive siblings would correlate to .00

Question 5

What is the heritability of personality traits?

Answer 5

Heritability of major personality traits is about 50%
•50% of individual differences are due to genetic factors.
•50% of individual differences are due to environmental factors.