Heritability

Heritability of Humor Appreciation

Early studies investigated whether humor appreciation, as measured by rating of the funniness of cartoons, has a genetic component. In a couple of such studies, pairs of twins were asked to rate different types of cartoons for funniness, and the correlations between the twins were measured. Results showed that the correlations of cartoon ratings among identical twins were no different than the fraternal twins for nonsense, satire, and sexual cartoons, meaning that shared familial environment, not genes, was the determinant factor for appreciation of these types of cartoons. Partial genetic influence was found for the appreciation of aggressive cartoons.

Genetic Contributions to Children's Humor

Studies compared children's sense of humor to their mothers, siblings, and friends. In one study, researchers asked teenagers to report the frequencies at which they like to tell jokes and laugh. Results showed similarities in humor uses between adolescents and their mothers and siblings but not with other friends who shared the same environment. More than 25% of the humor could be attributed to genetic factors. In another study, schoolchildren aged 9 to 11 years old were compared with their mothers, siblings, and friends on various measures of interpersonal humor. This study compared non-adoptive children (i.e., children living with their biological parents) to adoptive children. If humor has a strong genetic factor, we should find more similarities would be found between nonadoptive children and their mother and siblings compared with the adoptive children sample. The results showed that humor use with mothers and siblings can be ascribed to genetic factors. Just growing up within the same family does not make mothers' and siblings' humor similar, as evident by a lack of similarities in humor expression by children of adoptive parents.

Heritability of Humor Styles

Recently another approach to studying the heritability of humor was introduced. Researchers looked at four different humor styles (two positive, two negative) that people use in their daily life. The two positive styles are affiliative humor (the tendency to enjoy humor with others) and self-enhancing humor (having a humorous outlook on life). The two negative humor styles are aggressive humor (using humor to make fun of others) and self-defeating humor (self-disparaging humor, amusing others at one's own expense). In one large study, researchers compared adult identical and fraternal twins from the United Kingdom. Individual differences in all four humor styles were largely attributed to genetic and non-shared environmental factors. In another study with adult twins from a North American sample, results showed the use of two positive styles was attributed to genetic factors, but little genetic influence was found on the use of the two negative styles, meaning that individual differences on the negative styles were largely due to shared and nonshared environments. [Page 285]Differences in the two samples may have accounted for the somewhat inconsistent results.

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