Bystander Effect

Definition

In laboratory studies, the probability that any given individual helps falls as the number of bystanders rises.

Latané and Darley described a sequence of decisions a bystander must make — notice the event, interpret it as an emergency, take responsibility, decide how to help, act — and identified processes that can derail each one:

• Diffusion of responsibility: each person feels less responsible when others could act.
• Pluralistic ignorance: people look to others' calm reactions and conclude it is not an emergency.
• Audience inhibition: fear of looking foolish if one misreads the situation.

History

The research was prompted by the 1964 murder of Kitty Genovese in New York, reported by the New York Times as witnessed by 38 people who did nothing.

That account was substantially wrong. Later investigation found far fewer witnesses saw the attack, most heard only part of it, and at least two people tried to help, one of whom called the police. The story became a parable that psychology textbooks repeated for decades.

Darley and Latané's 1968 study, in which participants overheard someone apparently having a seizure, found that people who believed they were the only listener helped far more often and faster.

Theory

The effect is explained mainly by diffusion of responsibility and by the social definition of the situation.

Importantly, these processes weaken when the emergency is unambiguous and dangerous, when bystanders know each other, or when there is a clear social identity shared with the victim. Group size then matters less, and groups can be more likely to help because there are more potential helpers.

Research

A 2011 meta-analysis of more than 50 years of studies confirmed the effect but found it smaller in dangerous emergencies and when bystanders were not strangers.

A 2020 analysis of CCTV footage of real public conflicts in Amsterdam, Lancaster and Cape Town found that in about nine of ten incidents at least one bystander intervened, and the chance that someone helped rose with the number of people present — the opposite of the popular reading of the effect.

Applications

Bystander intervention training in universities, workplaces and public spaces, which teaches people to recognise situations, take responsibility, and choose a safe way to act — directly, by delegating, or by distracting.

In a real emergency, naming one specific person ('you in the blue coat, call an ambulance') counteracts diffusion of responsibility.

Criticism

• The Genovese story is mostly myth, and textbooks were slow to correct it.
• Individual versus group probability. Each person may be less likely to help while the victim is still more likely to be helped by someone in a larger group.
• Laboratory emergencies are artificial and mostly ambiguous, which is exactly where the effect is strongest.

References

• Darley, J. M., & Latané, B. (1968). Bystander intervention in emergencies: Diffusion of responsibility. Journal of Personality and Social Psychology, 8(4, Pt. 1), 377-383.
• Manning, R., Levine, M., & Collins, A. (2007). The Kitty Genovese murder and the social psychology of helping: The parable of the 38 witnesses. American Psychologist, 62(6), 555-562.
• Fischer, P., et al. (2011). The bystander-effect: A meta-analytic review on bystander intervention in dangerous and non-dangerous emergencies. Psychological Bulletin, 137(4), 517-537.
• Philpot, R., Liebst, L. S., Levine, M., Bernasco, W., & Lindegaard, M. R. (2020). Would I be helped? Cross-national CCTV footage shows that intervention is the norm in public conflicts. American Psychologist, 75(1), 66-75.