How does studying twins help understand the role of heredity and environment?We study twins to understand how much of the difference in a trait between people is caused by genes and how much is caused by the environment. These studies are important because they help scientists quantify genetic and modifiable environmental factors that increase the risk of certain diseases.
What do twin studies suggest about the role of heredity and personality?Twin studies of personality are consistent in attributing approximately half of the variance in personality to genetic effects, with the remaining variance attributed to environments that make people within the same families different.
What have we learned from twin and adoption studies about the role of genetics and environment nature and nurture in determining intelligence?The studies of reared-apart twins have shown that in general, half the differences in personality and religiosity are genetically determined, but for a trait like I.Q., about 75 percent of the variation, on average, is genetic, with only 25 percent influenced by the environment.
What do twin studies tell us about the importance of genetics on intelligence?Genes have a very strong influence over how certain parts of our brains develop, scientists in the US and Finland have found. And the parts most influenced are those that govern our cognitive ability.
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