What is the bystander effect?
The bystander effect is the tendency for each person to be less likely to help in an emergency when others are present. When everyone assumes someone else will act, responsibility thins out and no one moves.
- Proposed by
- John Darley and Bibb Latané (1968)
- Core finding
- More witnesses, lower individual likelihood of helping
- Main mechanisms
- Diffusion of responsibility, pluralistic ignorance, evaluation apprehension
- Applications
- Bystander intervention training, Good Samaritan laws
The Kitty Genovese case
In 1964 Kitty Genovese was murdered outside her home in Queens, New York. The New York Times reported that 38 neighbors watched and did nothing, and the story inspired a generation of research.
The famous version of the story was badly exaggerated. Manning, Levine and Collins (2007) showed that few witnesses saw the attack clearly and at least one person called the police. The parable was flawed, but the laboratory findings it inspired have largely held up.
Darley and Latané’s experiments
- Students talking over an intercom heard another participant apparently having a seizure (a recording).
- When participants believed they were the only listener, about 85% went for help before the seizure ended.
- When they believed four others were also listening, only about 31% did.
In a second study, participants alone in a room filling with smoke usually reported it, but far fewer did when sitting with confederates who ignored the smoke.
Why people don’t help
| Mechanism | What happens |
|---|---|
| Diffusion of responsibility | Each person feels only a fraction of the duty to act |
| Pluralistic ignorance | Everyone looks calm, so everyone concludes it isn’t serious |
| Evaluation apprehension | Fear of embarrassment if the help turns out to be unnecessary |
Latané and Darley described five steps to intervention: notice the event, interpret it as an emergency, accept responsibility, decide how to help, and act. Failure at any step means no help.
What newer research shows
A meta-analysis by Fischer and colleagues (2011) confirmed the effect but found it is weaker in clearly dangerous situations. Philpot and colleagues (2020) analyzed 219 CCTV recordings of real public conflicts in the UK, the Netherlands and South Africa; in about 90% of them at least one bystander intervened, and more bystanders meant a higher chance that someone helped.
Bullying and campus programs
In bullying, silent bystanders can signal approval to the aggressor. Many US schools and universities now run bystander-intervention programs, such as the "Green Dot" approach to sexual violence prevention, that teach direct, delegated and distracting ways to step in. See the Olweus bullying model for how roles in bullying work.
How to get help and how to give it
- When you need help, point to one person: "You in the red jacket, call 911." Singling someone out breaks diffusion of responsibility.
- As a witness, don’t assume someone else has called. Call 911 yourself.
- Learn CPR and how to use an AED so "not knowing how" is not the barrier.
Every US state has a Good Samaritan law protecting people who give reasonable emergency aid in good faith, though the details vary by state.
Frequently asked questions
- What is an example of the bystander effect?
- A crowd on a subway platform watching someone collapse while each person waits for someone else to act, or a group chat where no one challenges bullying.
- What causes the bystander effect?
- Mainly diffusion of responsibility, pluralistic ignorance (reading others’ calm as a sign nothing is wrong) and fear of embarrassment.
- Is the bystander effect real?
- Lab studies and meta-analyses support it, but real-world CCTV research shows that in public conflicts someone usually does intervene, especially when danger is obvious.
References
- Darley, J. M., & Latané, B. (1968). Bystander intervention in emergencies: Diffusion of responsibility. Journal of Personality and Social Psychology, 8(4), 377–383.
- Latané, B., & Darley, J. M. (1968). Group inhibition of bystander intervention in emergencies. Journal of Personality and Social Psychology, 10(3), 215–221.
- Fischer, P., Krueger, J. I., Greitemeyer, T., 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.
- 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.