This research investigates whether a contextual factor.social density, defined as the number of people in a given area.influences consumers. propensity to share information. We propose that high- (vs. low-) density settings make consumers experience a loss of perceived control, which in turn makes them more likely to engage in word of mouth to restore it. Six studies, conducted online as well as in laboratory and naturalistic settings, provide support for this hypothesis. We demonstrate that social density increases the likelihood of sharing information with others and that a person.s chronic need for control moderates this effect. Consistent with the proposed process, the effect of social density on information sharing is attenuated when participants have the opportunity to restore control before they engage in word of mouth. We also provide evidence that sharing information restores perceived control in high-density environments, and we disentangle the effect of social density from that of physical proximity.