PSYCH 2B03 Lecture : Biological Bases of Personality (2).docx

• School: McMaster University
• Department: Psychology
• Course: PSYCH 2B03
• Professor: Judith Shedden

Document Summary

Heritability coefficient: h2, most commonly calculated measure of the relative significance of genetic vs environmental factors. 2 = sum (score mean)2/number of scores, average squared deviation of individual scores from the mean. When you calculate a correlation, it also involves a ratio of variances ratio of variance. H2=rmza should lead to the highest estimate of variability, assuming environments are uncorrelated which means that all of the similarity must be due to their genetic similarity. H2=2rdza correlation between dizygotic twins reared apart and double it cannot use mz reared together because there are two reasons for their similarities, their genetic and environmental similarities. Applies only to groups, not individuals: half the differences is due to genetic or environmental. Varies from population to population, and over time: not a constant, where the sources of variability come from. Valid only if measures used to calculate it are valid sources of environmental variation are reduced, for example: rate of poverty, health care, etc.