When people get together in groups, unusual things can happen, both good and bad. Groups create important social institutions that an individual could not achieve alone but there can be a darker side to such alliances.
Belonging to a group makes people more likely to harm others outside the group as they lose touch with their own morals.
Several other factors play into this transformation. When people are in a group, they feel more anonymous, and less likely to be caught doing something wrong. They may also feel a diminished sense of personal responsibility for collective actions.
Rebecca Saxe, an associate professor of cognitive neuroscience at MIT said that a group of people will often engage in actions that are contrary to the private moral standards of each individual in that group, sweeping otherwise decent individuals into 'mobs' that commit looting, vandalism, even physical brutality.
The study is published online in the journal NeuroImage.