Won’t somebody stop him? SolStock/Getty

If you were being attacked, would anyone stop to help you? A famous result in psychology known as the bystander effect says probably not, but now a review of real-life violent situations says this commonly held view may be wrong.

The bystander effect purports that in situations such as a robbery or a stabbing, bystanders are less likely to step in if there are a large number of people in the area, so the likelihood of intervention decreases.

The idea has its roots in the 1964 case of Kitty Genovese, a 28-year-old woman who was raped and murdered in the early morning in her quiet neighbourhood in Queens, New York. The New York Times reported at the time that 38 people had watched for more than half an hour as she was attacked.


It turns out that the number of observers in that case was an exaggeration, but the incident has become part of psychology legend. The bystander effect, first proposed by social psychologists Bibb Latané and John Darley, has been replicated in numerous experimental studies.

Potential explanations for the phenomenon include that individuals may feel less responsibility to intervene when many other people are around, as well as fear acting inadequately when being observed. It may also be that if no one else seems to be reacting or taking action, then we may fail to perceive the situation as an emergency.

Now, Richard Philpot at Lancaster University in the UK and his colleagues say the effect might not actually be real. They looked at surveillance footage of violent situations in the UK, South Africa and the Netherlands, and found that, in 90 per cent of cases, at least one person (but typically several) intervened and tried to help.

In addition, they found that the likelihood of intervention increased in accordance with the number of bystanders – which directly contradicts the bystander effect.

Philpot says he hopes that the general public will find the results of the paper reassuring. “The more people around, the greater number of people who have the potential or the willingness to do something.”

The researchers were surprised to find that the likelihood of intervention was similar across all three nations, despite South Africa having on record significantly lower perceptions of public safety, as well as higher levels of violence, on average. Philpot says it shows that people have a natural inclination to help when they see someone in need.

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Jay Van Bavel of New York University says the results are “very striking”. The Kitty Genovese case is one of the core studies taught in undergraduate psychology classes, and the fact that this study contradicts a lot of the previous research is shocking, but exciting for the field.

Philpot and his colleagues are interested in looking at how specific factors such as the size of the perpetrator or whether they have a weapon influence people’s likelihood of intervening. “I wouldn’t say in every single situation it’s a 90 per cent likelihood, but as a base rate, it’s something new that we didn’t have before,” he says.

Journal reference: American Psychologist, DOI: 10.1037/amp0000469