The Bystander Effect

The Bystander Effect is a term that describes the phenomenon whereby individuals or groups of people ignore someone in distress (calling for help, being attacked, being abused) rather than going to help. Research has found that the more bystanders there are at an event the less likely any one person is to help.

The term was coined after an infamous incident in New York in 1964 in which a woman was brutally murdered within earshot of many neighbours, who appeared not to respond to her cries of help.  This incident spawned a large number of social psychology experiments to document and understand this behaviour.