Social networking sites have determined radical changes in human life, demanding investigations on online socialization mechanisms. The knowledge acquired on in-person sociability could guide researchers to consider both environmental and genetic features as candidates of online socialization. Here, we explored the impact of the quality of adult attachment and the genetic properties of the Serotonin Transporter Gene (5-HTTLPR) on Instagram social behavior. Experiences in Close Relationships-Revised questionnaire was adopted to assess 57 Instagram users' attachment pattern in close relationships with partners. Genotypes from the 5-HTTLPR/rs25531 region were extracted from the users' buccal mucosa and analyzed. Users' Instagram social behavior was examined from four indexes: number of posts, number of followed users ("followings") and number of followers, and the Social Desirability Index calculated from the followers to followings ratio. Although no interaction between rs25531 and ECR-R dimensions was found, an association between avoidance in close relationships and Instagram number of followings emerged. Post hoc analyses revealed adult avoidance from the partner predicts the Instagram number of followings with good evidence. Moreover, users reporting high avoidance levels displayed fewer followings than users who reported low levels of avoidance. This research provides a window into the psychobiological understanding of online socialization on Instagram.
Keywords: Instagram; avoidance; close relationship; gene x environment; online behavior; rs25531; serotonin transporter gene; social networking sites.