The Bystander Effect: Why Crowds Can Fail to Help

It seems reasonable to suppose that a person in trouble is safest when there are many people around to help. Surely the more witnesses there are to an emergency, the more likely it is that someone will step in. Yet a large body of research in psychology suggests that, very often, exactly the opposite is true. The presence of other people can make each individual less, rather than more, likely to offer help. This surprising pattern is known as the bystander effect, and it has become one of the best-known findings in the study of social behaviour.

Serious study of the phenomenon began in the 1960s, prompted by a widely reported crime in a large American city. According to the accounts that circulated at the time, a woman was attacked in a public place while many neighbours, it was said, heard or saw something of what was happening, yet no one came to her aid or called for help until it was too late. The story caused a public outcry and puzzled psychologists, who set out to understand how so many people could apparently have done nothing. Their experiments, carried out in the years that followed, transformed a shocking anecdote into a carefully studied effect. Later historians would question whether the original events had been reported quite as accurately as the newspapers of the day suggested, but by then the research the case had inspired had taken on a life of its own, resting on evidence gathered under controlled conditions rather than on the details of any single incident.

Researchers staged emergencies of various kinds and observed how people reacted, sometimes when alone and sometimes in the company of others. The results were consistent and striking: as the number of witnesses increased, the likelihood that any one of them would help actually went down, and help, when it came at all, tended to arrive more slowly. A person who would readily assist a stranger when the two of them were alone might stand by and do nothing when surrounded by a crowd of other onlookers, each apparently as passive as the rest.

Two main explanations were put forward for this behaviour. The first is what psychologists call the diffusion of responsibility. When a person is the only witness to an emergency, the responsibility to act rests entirely on their shoulders. But when many others are present, that responsibility is felt to be shared among the whole group, and each individual assumes, often wrongly, that someone else will surely deal with the problem. Since everyone reasons in the same way, it can happen that no one acts at all, each waiting for another to take the lead.

The second explanation concerns the way people look to others for guidance about how to behave. In an ambiguous situation, where it is not clear whether there is really an emergency, people glance at those around them to judge how serious things are. If everyone else appears calm and unconcerned, each person takes this outward calm as a sign that nothing is truly wrong, and so does nothing in turn. The trouble is that all the witnesses may be doing exactly the same thing, each misled by the apparent composure of the others, so that a whole group can talk itself into inaction. Psychologists call this shared misreading pluralistic ignorance.

Understanding the bystander effect does more than explain a troubling pattern; it also points to ways of overcoming it. The key, researchers have found, is to break through the diffusion of responsibility by making it personal. A victim who calls out to the crowd in general is easily ignored, but one who singles out a particular individual, pointing directly at one person and asking clearly for a specific kind of help, is far more likely to receive it. Once responsibility is placed squarely on a named individual, the psychological escape route of assuming that someone else will act is closed off, and people generally respond. Far from being a sign that human beings are simply callous, the bystander effect turns out to be a predictable result of ordinary social psychology, and one that a little knowledge can help to defeat. Simply knowing that the effect exists, researchers suggest, makes a person more likely to step forward when others hang back.