Prosocial Behavior: Why People Help Others

Prosocial behavior is any action intended to benefit others — helping, sharing, comforting, cooperating, or volunteering. It is one of social psychology’s most hopeful topics, and also one of its most puzzling: people regularly help strangers at cost to themselves, yet in some of the most famous cases on record, crowds of bystanders have watched an emergency and done nothing. Understanding both halves of that puzzle — why people help and why they sometimes don’t — is the subject of this article, including the bystander effect, which is covered here rather than as a separate article.

This article is educational, not clinical. It describes prosocial behavior research, including studies of emergencies. It is not advice about intervening in any specific situation, where personal safety and local emergency services come first.

What Prosocial Behavior Means

Prosocial behavior is a broad category. It includes altruism — helping motivated by concern for the other person, even at a cost to yourself — but also helping motivated by other reasons: reputation, reciprocity, mood, or social norms. Donating anonymously and donating publicly are both prosocial, but they may have different motives, and social psychology is careful to separate the behavior (helping) from the motive (why). Cooperation, sharing, and comforting all count, as does volunteering time for a cause.

Helping varies by relationship and cost. People help kin most readily, friends next, and strangers least — a pattern consistent with both evolutionary and social explanations. They also help more when the cost is low and the need is clear, and less when helping is risky, ambiguous, or likely to be punished. These patterns are not cynical; they describe the conditions under which a good impulse turns into action, which is the practical question the research tries to answer.

The Bystander Effect

The bystander effect is the finding that people are less likely to help in an emergency when other bystanders are present. It entered psychology after the 1964 murder of Kitty Genovese in New York, whose case — as originally reported — suggested neighbors heard her cries and did nothing. Later historical work has shown the original newspaper account was substantially exaggerated: several neighbors did call police or shout at the attacker, and the “38 witnesses who did nothing” story is a myth. The research the case inspired, however, is real and has been replicated many times.

John Darley and Bibb Latané (1968) tested the effect experimentally. Participants believed they were discussing problems over an intercom with other participants; one “participant” (a recording) appeared to have a seizure and call for help. When participants believed they were the only listener, most intervened quickly. When they believed four others were also listening, far fewer intervened, and those who did took much longer. The presence of others did not make participants crueler — it changed their reading of the situation and their sense of personal responsibility.

Why Bystanders Don’t Act

Latané and Darley identified three mechanisms. The first is diffusion of responsibility: with several bystanders, the responsibility to act is shared, so each person feels less personally obliged — someone else will surely do it. The second is evaluative apprehension: people fear being judged for overreacting, misreading the situation, or embarrassing themselves, so they hesitate in public. The third is pluralistic ignorance: each bystander looks at the others, sees calm faces, and concludes nothing serious is happening — while every other bystander is doing the same thing, producing a group of concerned people who collectively look unconcerned. Pluralistic ignorance works as a form of conformity, since each bystander follows the group’s apparent inaction.

These mechanisms explain why the bystander effect is strongest in ambiguous situations. A clear emergency — someone shouting for help, visible injury — breaks through pluralistic ignorance, and helping rises. An ambiguous one — someone lying on the pavement who might be sleeping, ill, or drunk — lets all three mechanisms operate at once. The effect is also weaker when bystanders know each other, when one person is singled out, or when someone else acts first, which breaks the spell of inaction.

When People Do Help

People help most when the situation is clear, the need is unambiguous, and they feel personally responsible. Piliavin, Rodin, and Piliavin (1969) studied helping in a natural setting: staged collapses on subway trains. A person who collapsed appearing ill received help quickly and almost always; a person who collapsed appearing drunk received help more slowly and less often. The difference was not the bystanders’ character but their reading of the situation: illness evoked sympathy and a clear duty, while drunkenness evoked blame and uncertainty about whether help was wanted.

Other factors reliably raise helping. A good mood increases it; feeling guilty increases it; being in a hurry decreases it. Similarity helps — we assist people we see as like us. So does perceived deservingness, which is why the same need draws different responses depending on how the victim is framed. And direct requests help enormously: being singled out (“You, call an ambulance”) dissolves diffusion of responsibility and converts a bystander into a responsible agent. That single fact is the basis of most bystander-intervention training. Helping can also follow direct instructions, since obedience to an authority figure can turn a bystander into a helper.

Altruism or Self-Interest?

The deepest debate in the field is whether truly selfless helping exists. Daniel Batson (1991), in The Altruism Question, argued for the empathy-altruism hypothesis: when you feel empathic concern for someone in need, you are motivated to help them for their own sake, not yours. His experiments showed that people induced to feel empathy helped even when they could easily escape the situation without helping — the signature test of altruism, since escape removes any self-interested reason to stay.

Critics reply that empathic helping still serves the helper: it relieves the helper’s own distress at witnessing suffering, preserves a self-image as a good person, or anticipates social reward. The debate has not been settled, and it may not have a clean answer, because most helping mixes motives — a person can genuinely care about the victim and also feel better for helping. What the evidence does establish is that empathy reliably increases helping, whatever its ultimate motive, and that perspective-taking — imagining the other person’s experience — is one of the strongest known levers for turning bystanders into helpers.

Helping in Everyday Life

Most prosocial behavior is not dramatic. It is holding a door, giving directions, donating blood, mentoring a colleague, or volunteering regularly — small, repeated acts that sustain communities. Research on volunteering finds that regular helpers report greater well-being and social connection, though the direction of causation runs both ways: happy people volunteer more, and volunteering makes people happier. Organizations that want more helping therefore focus on lowering barriers — making the need visible, the action easy, and the responsibility personal — rather than on exhorting people to be better.

The bystander literature offers the clearest practical lesson. If you witness an emergency, the research suggests: treat ambiguity as a reason to check, not to wait; single out individuals for specific tasks rather than appealing to the crowd; and act first, because your action gives every other bystander permission to act too. Communities that teach these steps — many campuses and workplaces now do — are applying social psychology directly, turning a laboratory finding into a public good.

Key Takeaways

Prosocial behavior is action intended to benefit others, including helping, sharing, comforting, cooperating, and volunteering.
The bystander effect (Darley & Latané, 1968) is that people are less likely to help when other bystanders are present; the original Genovese newspaper account was substantially exaggerated, but the experimental effect is real.
Three mechanisms explain it: diffusion of responsibility, evaluative apprehension, and pluralistic ignorance.
Helping rises when the need is clear, the victim seems deserving, and responsibility is personal — being singled out is especially powerful.
Piliavin and colleagues (1969) found subway passengers helped an ill-appearing victim quickly and almost always, but a drunk-appearing victim more slowly.
Batson (1991) argued empathy produces genuinely altruistic motivation; critics note helping may still serve the helper, and most real helping mixes motives.

References

Batson, C. D. (1991). The Altruism Question: Toward a Social-Psychological Answer. Lawrence Erlbaum Associates.
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. https://doi.org/10.1037/h0025589
Latané, B., & Darley, J. M. (1970). The Unresponsive Bystander: Why Doesn’t He Help? Appleton-Century-Crofts.
Piliavin, I. M., Rodin, J., & Piliavin, J. A. (1969). Good Samaritanism: An underground phenomenon? Journal of Personality and Social Psychology, 13(4), 289–299. https://doi.org/10.1037/h0028433

Keep Exploring

What is prosocial behavior?

Any action intended to benefit others — helping, sharing, comforting, cooperating, or volunteering — whether motivated by altruism or by other reasons such as reputation or reciprocity.

What is the bystander effect?

The finding that people are less likely to help in an emergency when other bystanders are present, demonstrated experimentally by Darley and Latané (1968).

Why don’t bystanders help?

Three mechanisms: diffusion of responsibility (someone else will act), evaluative apprehension (fear of overreacting publicly), and pluralistic ignorance (others’ calm faces suggest nothing is wrong).

Did 38 witnesses really do nothing in the Kitty Genovese case?

No. Later historical work showed the original newspaper account was substantially exaggerated — several neighbors did call police or shout at the attacker — though the case inspired real bystander research.

Is helping ever truly selfless?

Batson (1991) argued empathy produces genuinely altruistic motivation, shown when people help even when they could easily escape; critics note helping also relieves the helper’s distress, so most real helping likely mixes motives.

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