Diffusion of Responsibility
A reduced sense of personal accountability which tends to occur in groups without an assigned leader or other responsible party. Diffusion of responsibility can cause group members to participate in behaviors they would never take part in alone.
Example: The hierarchical nature of the Nazi party allowed minor bureaucrats to claim that they were just following orders, and their supervisors to argue that they had merely issued commands and not performed actual deeds; no one claimed direct responsibility for the millions of murders for which their organization was responsible.
Grinnell, R. (2008). Diffusion of Responsibility. Psych Central. Retrieved on May 28, 2015, from http://psychcentral.com/encyclopedia/2008/diffusion-of-responsibility/