Objective: This study examines temporal patterns and individual differences of overestimation in alcohol norm perception within a social network.
Design: Hundred psychology freshmen indicated biweekly during their first semester the drinks they consumed, the perceived average of their peers’ consumption, and with whom they were acquainted. At baseline, trait self-control was assessed.
Main outcome: The moderation of alcohol consumption overestimation by time and individual characteristics was explored.
Results: Results show that students overestimated alcohol consumption of their acquainted peers by 1.22 drinks (p  .001). For time periods at which peers reported high consumption, overestimation decreased. Additionally, individuals reporting high alcohol consumption (b = −0.25, p  .001) and low self-control (b = 0.27, p = .010) showed higher overestimation.
Conclusions: Students overestimate the alcohol consumption of peers not fully accounting for changes in peer-reports. Furthermore, individual differences suggest informational and motivational processes underlying overestimation.