The size and homophily of friendship networks are to a substantial degree based on genetic influence; no evidence found that shared hobbies, education, or Big Five personality traits affect networks

Heritability in friendship networks. Michael Neugart, Selen Yildirim. Journal of Economic Behavior & Organization, Volume 194, February 2022, Pages 41-55. https://doi.org/10.1016/j.jebo.2021.12.008

Highlights

• Heritability of overall friendship network characteristics is explored.

• Data from German TwinLife Study is analyzed within classical twin design.

• Genetic component found in twins’ network size and network homophily.

• Role of twins’ shared hobbies, education, and personality traits is analyzed.

Abstract: There is considerable evidence nowadays that friendship networks account for a large part of an individual’s success or failure in life. Little, however, is known about the extent to which friendship networks are associated with an individual’s genotype. Using data from the German TwinLife study, we explore, within a classical twin design, whether friendship networks are related to genes. We find a substantial heritability component in twins’ network sizes and network homophily, but not in twins’ network closeness. The genetic influence on network characteristics may be attributable to traits which are themselves influenced by genetic factors. Addressing indirect ways in which genes could influence network characteristics, we do not find evidence that shared hobbies, education, or Big Five personality traits affect networks.

Keywords: Social networksTwinsBehavioral geneticsHobbiesBig fiveEducation