How do passengers influence drivers’ propensities for angry driving? Different effects of supervisors versus friends

A lot of researchers discussed the influence of passengers on drivers’ behaviors without reaching a consistent conclusion. This study aimed to offer some new evidence concerning this issue. The study examined different effects of supervisors and friends as passengers on drivers’ propensities for angry driving. In Study 1, drivers were asked to freely imagine a passenger either as their supervisor or friend. Results showed that compared with driving alone, drivers’ propensities for angry driving increased when the passenger was a friend but decreased when the passenger was a supervisor. These findings were consistent with the generally accepted social norm. In Study 2, drivers read a description about either an aggressive supervisor or a cautious friend. Results showed that the effects of passengers on drivers’ angry driving propensities were correspondingly reversed, indicating that a clearer behavior standard conveyed by a passenger had a stronger effect on drivers. Self-monitoring propensity showed a main effect on drivers’ propensities for angry driving in a standard-free situation. And self-monitoring propensity moderated the effect of a passenger's role on angry driving propensities in a standard-set situation. Impression management processes were discussed with respect to these findings.