Van Bommel, M., Van Prooijen, J.-W., Elffers, H., & Van Lange, P. A. M. (2012). Be aware to care: Public self-awareness leads to a reversal of the bystander effect. Journal of Experimental Social Psychology, 48, 926-930.

Abstract:

The classic bystander effect stipulates that people help others more when they are alone than when other bystanders are present. We reason that, sometimes, the presence of bystanders can increase helping, notably in situations where public self-awareness is increased through the use of accountability cues (e.g., a camera). We conducted two experiments in which we tested this line of reasoning. In both experiments, participants read messages soliciting support in an online forum. We varied the number of people that were present in that forum to create a bystander and an alone condition. In Study 1, we introduced an accountability cue by making participants' screen-names more salient, and in Study 2, we used a webcam. Both studies indicate that, as expected, the bystander effect can be reversed by means of cues that raise public self-awareness in social settings.