Bystander Effect

Finding that people help less in emergencies as the number of other witnesses grows: responsibility diffuses.

Specifications & Metrics

In Darley and Latané's seizure experiment, 85 percent of participants alone sought help, versus 31 percent who believed four others were present.
Diffusion of responsibility, not apathy, is the standard account: each witness assumes someone else will act.
Later research adds boundary conditions: bystanders help more when they know each other or can see one another.