PSYC 2740 Lecture Notes - Lecture 8: Twin Study, Behavioural Genetics, Heritability

• School: University of Guelph
• Department: Psychology
• Course: PSYC 2740
• Professor: Lewis Stephen

Document Summary

Percent of variance: difference between people due to a certain cause (in percentages, environment, genetics. Heritability vs. environmentality: heritability, amount of phenotypic variance in a group due to genotypic variance, genotypic variance. Environmentality: amount of observed variance due to environment. Examine correlations between: genetic relatedness of family members, personality similarity. Parents & children: 50: grandparents & grandchildren: 25% Siblings: 50: closer relatives should have more personality similarity. Bg methods: twin studies: monozygotic (mz) twins, dizygotic(dz) twins, estimate heritability via similarity of, mz vs. dz twins. Bg methods: twin studies cont"d: heritability formula, heritability2 = 2(rmz rdz) rmz = correlation between mz twins for a trait rdz = correlation between dz twins for a trait. Bg methods: twin studies - critical assumption equal environments: environments for mz twins no different vs. dz twins. Examine correlations between: adopted children & adoptive parents, also: adopted children & birth parents. Bg methods: adoption studies limitations: assumption of representativeness, children/parents represent general population.