Similarity of problematic smartphone use within social relationships: The role of social reward

Background and aims Individuals with close social relationships often exhibit similar levels of problematic smartphone use (PSU), suggesting that PSU may be interconnected through social influence. However, the underlying cognitive processes remain unclear. Methods To address this gap, two studies were conducted to examine the role of social reward valuation in the mutual influence between friends' smartphone use behaviors. Social reward was manipulated by informing participants of their friends' preferences during joint leisure activity selections. Study 1 measured the subjective value of social reward by incorporating a parameter into a drift diffusion model. Study 2 further examined the effect of relationship duration on social reward valuation during joint leisure activity selections. Results The results of Study 1 showed that individuals tended to change their own preferences when they differed from those of their friends, and this tendency could be explained by the subjective value they assigned to social rewards. Moreover, dyadic PSU moderated this process: greater similarity in friends' PSU predicted higher social reward valuation. The results in Study 2 showed that relationship duration was positively associated with social reward valuation and mediated the association between friends' PSU similarity and social reward valuation. Discussion and Conclusions Taken together, these findings suggest that similarity in friends' PSU enhances the subjective value of social rewards, which in turn leads individuals to follow their friends' smartphone use behaviors. This influence was further associated with longer relationship duration.