The Bystander Effect

Why Bystanders Sometimes Fail to Help

The bystander effect
Iwan Beijes

If you witnessed an emergency happening right before your eyes, you would certainly take some sort of action to help the person in trouble, right? While we might all like to believe that this is true, psychologists suggest that whether or not you intervene might depend upon the number of other witnesses present.

Understanding the Effect

The term bystander effect refers to the phenomenon in which the greater the number of people present, the less likely people are to help a person in distress.

When an emergency situation occurs, observers are more likely to take action if there are few or no other witnesses. Being part of a large crowd makes it so no single person has to take responsibility for an action (or inaction).

In a series of classic studies, researchers Bibb Latane and John Darley  found that the amount of time it takes the participant to take action and seek help varies depending on how many other observers are in the room. In one experiment, subjects were placed in one of three treatment conditions: alone in a room, with two other participants or with two confederates who pretended to be normal participants.

As the participants sat filling out questionnaires, smoke began to fill the room. When participants were alone, 75% reported the smoke to the experimenters. In contrast, just 38% of participants in a room with two other people reported the smoke. In the final group, the two confederates in the experiment noted the smoke and then ignored it, which resulted in only 10% of the participants reporting the smoke.

Additional experiments by Latane and Rodin (1969) found that while 70 percent would help a woman in distress when they were the only witness, only about 40 percent offered assistance when other people were also present.

Example of the Bystander Effect

The most frequently cited example of the bystander effect in introductory psychology textbooks is the brutal murder of a young woman named Catherine "Kitty" Genovese.

On Friday, March 13, 1964, 28-year-old Genovese was returning home from work. As she approached her apartment entrance, she was attacked and stabbed by a man later identified as Winston Moseley.

Despite Genovese’s repeated calls for help, none of the dozen or so people in the nearby apartment building who heard her cries called the police to report the incident. The attack first began at 3:20 AM, but it was not until 3:50 AM that someone first contacted police.

Initially reported in a 1964 New York Times article, the story sensationalized the case and reported a number of factual inaccuracies. While frequently cited in psychology textbooks, an article in the September 2007 issue of American Psychologist concluded that the story is largely misrepresented mostly due to the inaccuracies repeatedly published in newspaper articles and psychology textbooks.

While Genovese's case has been subject to numerous misrepresentations and inaccuracies, there have been numerous other cases reported in recent years.

The bystander effect can clearly have a powerful impact on social behavior, but why exactly does it happen? Why don't we help when we are part of a crowd?

Explanations for the Bystander Effect

There are two major factors that contribute to the bystander effect.

First, the presence of other people creates a diffusion of responsibility. Because there are other observers, individuals do not feel as much pressure to take action, since the responsibility to take action is thought to be shared among all of those present.

The second reason is the need to behave in correct and socially acceptable ways. When other observers fail to react, individuals often take this as a signal that a response is not needed or not appropriate. Other researchers have found that onlookers are less likely to intervene if the situation is ambiguous. In the case of Kitty Genovese, many of the 38 witnesses reported that they believed that they were witnessing a "lover's quarrel," and did not realize that the young woman was actually being murdered.

Characteristics of the situation can play a role. During a crisis, things are often chaotic and the situation is not always crystal clear. Onlookers might wonder exactly what is happening. During such chaotic moments, people often look to others in the group to determine what is appropriate. When people look at the crowd and see that no one else is reacting, it sends a signal that perhaps no action is needed.

Can You Prevent the Bystander Effect?

So what can you do to avoid falling into this trap of inaction? Some psychologists suggest that simply being aware of this tendency is perhaps the greatest way to break the cycle. When faced with a situation that requires action, understanding how the bystander effect might be holding you back and consciously taking steps to overcome it can help. However, this does not mean you should place yourself in danger.

But what if you are the person in need of assistance? How can you inspire people to lend a hand? One often-recommended tactic is to single out one person from the crowd. Make eye contact and ask that individual specifically for help. By personalizing and individualizing your request, it becomes much harder for people to turn you down.

Related Reading:


Kitty Genovese: What Really Happened? – Learn more in this episode of Michael Britt’s excellent podcast series The Psych Files


Darley, J. M. & Latané, B. (1969). Bystander “apathy.” American Scientist, 57, 244-268.

Latané, B. and Darley, J. M. (1970) The unresponsive bystander: Why doesn’t he help? Englewood Cliffs, NJ: Prentice Hall.

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, 2007;62(6): 555-562.

Soloman, L.Z, Solomon, H., & Stone, R. (1978). Helping as a function of number of bystanders and ambiguity of emergency. Personality and Social Psychology Bulletin, 4, 318-321.

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