Outgroup threat and group cohesion
Martin Lang et al. published an article studying the effects of outgroup threat on intragroup cohesion in Group Processes & Intergroup Relations.
Synchrony and group moral hypocrisy
While motoric synchronization plays an important role in cooperation and cohesion in smaller groups, it can lead to moral hypocrisy in favor of a smaller sub-group within larger groups. Radim, Radek, and Martin studied such hypocrisy in an experiment manipulating the rate of synchronization.
Their data suggest that participants highly synchronized with the confederate judged his moral transgression less harshly, with the effect mediated by the participants’ feeling of being a part of the same group as the confederate. According to Radim, Radek, and Martin, this effect can help explain nepotism and cronyism, as generating cooperation and cohesion in a face-to-face manner in smaller groups can undermine cooperation in larger groups. They also discuss that cooperation in larger groups needs to overcome these tribal mechanisms by associating them with largely shared and emotionally charged symbols provided by moralizing gods, state ideologies, or social institutions.
You can find the article here:
