Is Expressing Affection Heritable?
Affectionate behavior is important for relationship maintenance and satisfaction. To what degree is expressing or receiving affectionate behavior heritable? In a recent article published in NCA’s Communication Monographs, Kory Floyd, Chance York, and Colter D. Ray share their results from a twin study that examined how affectionate behavior is influenced by shared genetic heritage, shared environmental factors (such as growing up in the same household), and non-shared environmental factors (such as individual experiences).
Affectionate Communication as a Trait and Affection Exchange Theory
Affectionate behavior is generally understood to refer to affection toward others, manifested through such actions as expressions of closeness or care. Although an individual’s affectionate behavior may vary depending on context, “people also have relatively stable tendencies to enact a certain level of affectionate behavior – whether high, medium, or low – in most of their relationships.” Affection exchange theory postulates that affectionate behavior is related to human survival. If human beings need affection (and to be affectionate) for survival, then to what degree is affectionate behavior innate, rather than learned? Previous studies suggest that there are at least two genes associated with affectionate behavior.
Floyd, York, and Ray conceptualize affectionate communication as expressed affection (the affection one shows toward others) and received affection (the affection others show toward oneself). Expressed and received affection are reciprocal. This means that if someone shows affection to you, you are likely to return affection. However, the two may also be correlated by genetics, which this study considers.
Twin studies have been used to examine inheritability for more than 50 years. For the study, the researchers recruited 928 adult twins (464 pairs) using the Washington State Twin Registry. Study participants included 229 identical twin pairs, and 235 fraternal twin pairs. The vast majority (96.2 percent) were white. There were nearly equal numbers of men and women. Most of the participants (69.5 percent) had stopped living with their twin siblings between the ages of 18 and 21.
Participants filled out a survey that measured trait expressed affection and trait received affection. Results showed that women scored higher on both traits. The results also showed that “identical twins were more similar on each measure than were fraternal twins” on both traits. In addition, twins over the age of 50 showed a stronger correlation for received affection, compared to twins under 50.
Floyd, York, and Ray found that about 45 percent of the variance in trait expressed affection was heritable and 55 percent was attributable to unique environmental factors. Trait received affection was less heritable and more dependent on social and environmental factors; the researchers’ model showed that about 21 percent of the variance in received affection was accounted for by genetics, 14 percent by common environmental factors, and 65 percent by unique environmental influences.
Floyd, York, and Ray argue that the findings about the heritability of trait expressed affection align with results of studies of similar traits. They note that received affection is “a more socially contingent trait than trait expressed affection, which makes its lower heritability estimate unsurprising.” The results also showed that heritability was affected by participants’ age and sex. Floyd, York, and Ray write that the sex differences “may be evolutionarily adaptive” and that it may be advantageous for women’s survival to express and receive more affection. The stronger correlation for received affection among older adults may be related to other genetic factors, such as attractiveness. Finally, because both expressed and received affection were found to be heritable, Floyd, York, and Ray conclude that some of the previously observed relationship between received and expressed affection may be due to genetics, rather than demonstrated as a result of social expectations.
Importantly, Floyd, York, and Ray note that “attributing 45% of the overall variation in trait expressed affection to heritable genetic factors does not imply that 45% of a specific individual’s affectionate communication has a genetic basis… Heritability estimates gauge the extent to which traits differ between individuals in a population due to genetic variation.” Furthermore, while some traits may be heritable, this does not mean that any individual’s behavior is “preordained.” People are not defined by genes and can change their behaviors.