One reason twin studies produce higher estimates of heritability than some other methods may be that the twin studies
A. capturenonadditive effects of genetics.
B. often incorrectly classify dizygotic and monozygotic twins.
C. are based on small samples.
D. overlook gender differences.
Question 2The genetic influence of some personality traits may not be seen unless a specific combination of genes in inherited. Such complex influences are known as
A. monozygotic influences.
B. nonadditive effects.
C. combinatorial effects.
D. genetic correlations.
Question 3Some investigators suggest that genetic influences on personality may not be seen unless a unique combination of more than one gene is inherited. Researchers refer to these complex influences as ________ effects.
A. interactive
B. nonadditive
C. multiple-gene
D. compound
Question 4Which of the following hypothetical research findings would present a problem for researchers trying to interpret results from a twin-study design?
A. Parents of monozygotic twins treat the two twins more alike than do parents of dizygotic twins.
B. Dizygotic twins don't look as much like one another as do monozygotic twins.
C. Parents treat female pairs of twins differently than they treat male twins.
D. There are more dizygotic twins born each year than monozygotic twins.
Question 5Research on genetic determinants of personality tell us that
A. personality is fixed at birth.
B. most, but not all, of adult personality is determined by genetics.
C. a significant percentage of adult personality is determined by genetics, but experience also plays a large role.
D. except for a few traits, there is very little genetic influence on personality.
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