When it comes to behavioral genetics, is heritability (percentage of the variability in a trait across individuals that is due to genes) something that tells us whether or not traits can be changed? Is the number it displays permanent or fixed? Does it just apply to one individual? All of these questions are raised and answered in the section on Behavioral Genetics in Chapter 3. The chapter answers these questions using three misconceptions about what heritability truly is. These misconceptions have existed for a long time and continue to exist, because there is so much confusion on the subject, even among psychologists. (115)
The first misconception mentioned in the text is that "Heritability applies to a single individual rather than to differences among individuals." This is false, because heritability, in fact, only applies to groups of people. It gives us information about the causes of differences among groups of people. (115) The second misconception is concerned with the fact that many people tend to believe that traits with high heritability cannot be changed. Heritability does not say anything about alterable a trait is. Rather, according to Behavioral Geneticists, it is the "reaction range" that specifies how much a trait can change as a result of new environments. Lastly, the third misconception is that "Heritability is a fixed number." Heritability can change drastically across different time periods and populations. For example, if environmental influence is increased within a population, heritability will decrease, because there is less difference due to genetic factors. (116)
Overall, heritability is not a simple concept or one that everyone agrees on. However, it is one that is extremely important in the study genetics and behavior among humans. Hopefully, over time, misconceptions will be eliminated enough so that the definition of what heritability is and what its characteristics are is universally agreed upon.