The presence of other bystanders reduces an individual's likelihood of helping on average, with the effect moderated by danger and by who else is present.
Latané and Darley ran the studies after the 1964 Kitty Genovese killing, though the newspaper account of 38 unresponsive witnesses was later shown to be substantially wrong. The average effect holds across many studies, and it is moderated by danger, by whether other bystanders are passive or potentially supportive, and by the relationships among those present.
In practice
- A collapsed cyclist on a busy commuter platform is passed by hundreds; on an empty one, the first person stops.
- A hundred people are copied on an email asking who will handle an issue, and nobody does.
- Possible explanations
- One explanation is diffusion of responsibility, since each onlooker's share of the duty falls as the group grows. Another is pluralistic ignorance, in which everyone reads everyone else's stillness as evidence that nothing is wrong. A third is evaluation apprehension, the fear of intervening wrongly in public.
- In its favour
- The average effect survives meta-analysis across many studies, settings and decades.
- Against it
- Field evidence complicates it: an analysis of public conflicts recorded on street cameras found someone intervening in the great majority of them, and in clear emergencies more bystanders raise the chance that somebody acts.
- Standing
- The average effect holds, but it is moderated by danger, by who else is present, and by the relationships among them.
- Subject
- Psychology & Behavior
- Essay
- A century and a half of measuring the mind