The digital age has seen a rise in digital hoarding behavior, which is defined as the behavior of accumulating digital files, resulting in stress and disorder. However, little is known about the causes and psychological mechanisms of digital hoarding. To address this research gap, this study proposed and empirically tested a moderated mediation model of social networking site (SNS) users’ causes of and psychological motivation for digital hoarding behavior using an online questionnaire method. We surveyed a total of 556 SNS users online. The results revealed that social comparison of this sort increased individuals’ digital hoarding behaviors and that fear of missing out (FoMO) mediated this effect. In addition, dispositional greed moderated the relationship between this comparison and FoMO as well as the relationship between FoMO and digital hoarding behavior such that these relationships were stronger for SNS users with high dispositional greed. Our research improves our understanding of the operative psychological mechanisms and boundary conditions in the relation between upward comparison via SNSs and digital hoarding behavior.

Engaging in altruistic behaviors is costly, but it contributes to the health and well-being of the performer of such behaviors. The present research offers a take on how this paradox can be understood. Across 2 pilot studies and 3 experiments, we showed a pain-relieving effect of performing altruistic behaviors. Acting altruistically relieved not only acutely induced physical pain among healthy adults but also chronic pain among cancer patients. Using functional MRI, we found that after individuals performed altruistic actions brain activity in the dorsal anterior cingulate cortex and bilateral insula in response to a painful shock was significantly reduced. This reduced pain-induced activation in the right insula was mediated by the neural activity in the ventral medial prefrontal cortex (VMPFC), while the activation of the VMPFC was positively correlated with the performer’s experienced meaningfulness from his or her altruistic behavior. Our findings suggest that incurring personal costs to help others may buffer the performers from unpleasant conditions.

Dispositional greed, characterized by the insatiable hunger for more and the dissatisfaction for not having enough, has often been associated with heightened impulsivity and excessive risk-taking. Despite its far-reaching implications in social sciences and economics, however, the exact neural mechanisms of how greed personality influences risk-taking are still ill understood. In the present study, we showed the correlation between subject’s greed personality trait (GPT) score and risk-taking was selectively mediated by individual’s loss aversion, but not risk attitude. In addition, our neuroimaging results indicated that gain and loss prospects were jointly represented in the activities of the ventral striatum and medial orbitofrontal cortex (mOFC). Furthermore, mOFC responses also encoded the neural loss aversion signal and mediated the association between individual differences in GPT scores and behavioral loss aversion. Our findings provide a basis for understanding the specific neural mechanisms that mediate the effect of greed personality trait on risk-taking behavior.