The interaction between serotonin transporter allelic variation and maternal care modulates sociability on Instagram

In both physical and online environments, human social interactions can represent a means to gain recognition and approval from others. While there is considerable evidence about the interaction between genetics and the environment on social development, studies adopting the same framework to investigate online social interactions are lacking. The present work applies a model from behavioural genetics on Instagram sociability to explore the impact of individual development on social media platforms' behaviour. We hypothesized that social attitudes on Instagram resulted from an interaction between serotonin transporter gene alleles and the individual's remembrance of the interaction with caregivers. We assessed the environmental and genetic components of 57 Instagram users, adopting the Parental Bonding Instrument to determine the perceived parental care and overprotection. The number of posts followed by users ("followings") and followers were collected from participants' Instagram profiles as online social activity indexes. Additionally, the ratio between the number of followers and followings ("Social Desirability Index") was calculated to estimate each user's social network's asymmetry. Finally, information on the polymorphism rs25531 (T/T homozygotes vs C-carriers) within the serotonin transporter gene was extracted from participants' buccal mucosa cell samples. In line with the predictions, we found a gene-environment interaction on the Social Desirability Index": users with the genotype more sensitive to environmental influences (T/T homozygotes) showed a higher Instagram "Social Desirability Index" than less sensitive ones (C-carriers) when positive maternal care was experienced. This result may contribute to the understanding of online social behaviour from a gene*environment perspective.