People throughout the nation were shocked by the murder of 28-year-old Kitty Genovese in New York City. The facts of the case seemed to tear at our very social fabric as a nation. Kitty had screamed repeatedly for help as her killer had stalked her for more than half an hour and stabbed her in three separate attacks. Thirty-eight neighbors are known to have heard the commotion. Their voices and bedroom lights interrupted the assault twice. Yet nobody came to Kitty’s aid. No one even called the police. How could this happen? Some witnesses admitted that they had not wanted to get involved. One said that he was tired. Some simply said, "I don’t know."
Are these the reasons that no one came to the aid
of Kitty Genovese? As a nation, are we a callous bunch
who would rather watch than help when other people are
in need? News commentators spoke about the alienation
and dehumanization of city dwellers, particularly New
Yorkers. But John Darley and Bibb Latané, two
social psychologists, were not convinced that these
were the most important reasons. The two met at a party
shortly after the crime and mused about it for hours.
They then had a joint flash of inspiration: Perhaps
nobody helped precisely because they knew so many other
people were watching. Late that evening they began to
design an experiment to test what would become known
as the bystander effect. Like so many others of its
kind, this classic experiment relied on deceiving the
subjects as to the true purpose of the study.
Bystander Intervention in Emergencies: Diffusion of Responsibility
By JOHN M. DARLEY BIBB LATANé
NEW YORK UNIVERSITY COLUMBIA UNIVERSITY
Ss overheard an epileptic seizure. They believed either that they alone heard the emergency, or that 1 or 4 unseen others were also present. As predicted the presence of other bystanders reduced the individual’s feelings of personal responsibility and lowered his speed of reporting (p,.01). In groups of size 3, males reported no faster than females, and females reported no slower when the 1 other bystander was a male rather than a female. In general, personality and background measures were not predictive of helping. Bystander inaction in real-life emergencies is often explained by "apathy," "alienation," and "anomie." This experiment suggests that the explanation may lie more in the bystander’s response to other observers than in his indifference to the victim.
Several years ago, a young woman was stabbed to death in the middle of a street in a residential section of New York City. Although such murders are not entirely routine, the incident received little public attention until several weeks later when the New York Times disclosed another side to the case: at least 38 witnesses had observed the attack–and none had even attempted to intervene. Although the attacker took more than half an hour to kill Kitty Genovese, not one of the 38 people who watched from the safety of their own apartments came out to assist her. Not one even lifted the telephone to call the police (Rosenthal, 1964).
Preachers, professors, and news commentators sought the reasons for such apparently conscienceless and inhumane lack of intervention. Their conclusions ranged from "moral decay," to "dehumanization produced by the urban environment," to "alienation," "anomie," and "existential despair." An analysis of the situation, however, suggests that factors other than apathy and indifference were involved.
A person witnessing an emergency situation, particularly such a frightening and dangerous one as a stabbing, is in conflict. There are obvious humanitarian norms about helping the victim, but there are also rational and irrational fears about what might happen to a person who does intervene (Milgram & Hollander, 1964). "I didn’t want to get involved," is a familiar comment, and behind it lies fears of physical harm, public embarrassment, involvement with police procedures, lost work days and jobs, and other unknown dangers.
In certain circumstances, the norms favoring intervention may be weakened, leading bystanders to resolve the conflict in the direction of nonintervention. One of these circumstances may be the presence of other onlookers. For example, in the case above, each observer, by seeing lights and figures in other apartment house windows, knew that others were also watching. However, there was no way to tell how the other observers were reacting. These two facts provide several reasons why any individual may have delayed or failed to help. The responsibility for helping was diffused among the observers; there was also diffusion of any potential blame for not taking action; and finally, it was possible that somebody, unperceived, had already initiated helping action.
When only one bystander is present in an emergency, if help is to come, it must come from him. Although he may choose to ignore it (out of concern for his personal safety, or desires "not to get involved"), any pressure to intervene focuses uniquely on him. When there are several observers present, however, the pressures to intervene do not focus on any one of the observers; instead the responsibility for intervention is shared among all the onlookers and is not unique to any one. As a result, no one helps.
A second possibility is that potential blame may be diffused. However much we may wish to think that an individual’s moral behavior is divorced from considerations of personal punishment or reward, there is both theory and evidence to the contrary (Aronfreed, 1964; Miller & Dollard, 1941, Whiting & Child, 1953). It is perfectly reasonable to assume that, under circumstances of group responsibility for a punishable act, the punishment or blame that accrues to any one individual is often slight or nonexistent.
Finally, if others are known to be present, but their behavior cannot be closely observed, any one bystander can assume that one of the other observers is already taking action to end the emergency. Therefore, his own intervention would be only redundant–perhaps harmfully or confusingly so. Thus, given the presence of other onlookers whose behavior cannot be observed, any given bystander can rationalize his own inaction by convincing himself that "somebody else must be doing something."
These considerations lead to the hypothesis that the more bystanders to an emergency, the less likely, or the more slowly, any one bystander will intervene to provide aid. To test this proposition it would be necessary to create a situation in which a realistic "emergency" could plausibly occur. Each subject should also be blocked from communicating with others to prevent his getting information about their behavior during the emergency. Finally, the experimental situation should allow for the assessment of the speed and frequency of the subjects’ reaction to the emergency. The experiment reported below attempted to fulfill these conditions.
Procedure
OVERVIEW
A college student arrived in the laboratory and was ushered into an individual room from which a communication system would enable him to talk to the other participants. It was explained to him that he was to take part in a discussion about personal problems associated with college life and that the discussion would be held over the intercom system, rather than face-to-face, in order to avoid embarrassment by preserving the anonymity of the subjects. During the course of the discussion, one of the other subjects underwent what appeared to be a very serious nervous seizure similar to epilepsy. During the fit it was impossible for the subject to talk to the other discussants or to find out what, if anything, they were doing about the emergency. The dependent variable was the speed with which the subjects reported the emergency to the experimenter. The major independent variable was the number of people the subject thought to be in the discussion group.
SUBJECTS
Fifty-nine female and thirteen male students in introductory psychology courses at New York University were contacted to take part in an unspecified experiment as part of a class requirement.
METHOD
Upon arriving for the experiment, the subject found himself in a long corridor with doors opening off it to several small rooms. An experimental assistant met him, took him to one of the rooms, and seated him at a table. After filling out a background information form, the subject was given a pair of headphones with an attached microphone and was told to listen for instructions.
Over the intercom, the experimenter explained that he was interested in learning about the kinds of personal problems faced by normal college students in a high pressure, urban environment. He said that to avoid possible embarrassment about discussing personal problems with strangers several precautions had been taken. First, subjects would remain anonymous, which was why they had been placed in individual rooms rather than face-to-face. (The actual reason for this was to allow tape recorder simulation of the other subjects and the emergency.) Second, since the discussion might be inhibited by the presence of outside listeners, the experimenter would not listen to the initial discussion, but would get the subject’s reactions later, by questionnaire. (The real purpose of this was to remove the obviously responsible experimenter from the scene of the emergency.)
The subjects were told that since the experimenter was not present, it was necessary to impose some organization. Each person would talk in turn, presenting his problems to the group. Next, each person in turn would comment on what the others had said, and finally, there would be a free discussion. A mechanical switching device would regulate this discussion sequence and each subject’s microphone would be on for about 2 minutes. While any microphone was on, all other microphones would be off. Only one subject, therefore, could be heard over the network at any given time. The subjects were thus led to realize when they later heard the seizure that only the victim’s microphone was on and that there was no way of determining what any of the other witnesses were doing, nor of discussing the event and its possible solution with the others. When these instructions had been given, the discussion began.
In the discussion, the future victim spoke first, saying that he found it difficult to get adjusted to New York City and to his studies. Very hesitantly, and with obvious embarrassment, he mentioned that he was prone to seizures, particularly when studying hard or taking exams. The other people, including the real subject, took their turns and discussed similar problems (minus, of course, the proneness to seizures). The naive subject talked last in the series, after the last prerecorded voice was played.1
When it was again the victim’s turn to talk, he made a few relatively calm comments, and then, growing increasingly louder and incoherent, he continued:
I-er-um-I think I-I need-er-if-if could-er-er-somebody er-er-er-er-er-er-er give me a little-er-give me a little help here because-er-I-er-I’m-er-er-h-h-having a-a-a real problem- er-right now and I-er-if somebody could help me out it would-it would-er-er s-s-sure be-sure be good . . . because-er-there-er-er-a cause I-er-I-uh-I’ve got a-a one of the-er-sei–er-er-things coming on and-and-and I could really-er-use some help so if somebody would-er-give me a little h-help-uh-er-er-er-er-er c-could somebody-er-er-help-er-uh-uh-uh (choking sounds). . . . I’m gonna die-er-er-I’m . . . gonna die-er-help-er-er-seizure- er-[chokes, then quiet].
The experimenter began timing the speed of the real subject’s response at the beginning of the victim’s speech. Informed judges listening to the tape have estimated that the victim’s increasingly louder and more disconnected ramblings clearly represented a breakdown about 70 seconds after the signal for the victim’s second speech. The victim’s speech was abruptly cut off 125 seconds after this signal, which could be interpreted by the subject as indicating that the time allotted for that speaker had elapsed and the switching circuits had switched away from him. Times reported in the results are measured from the start of the fit.
GROUP SIZE VARIABLE
The major independent variable of the study was the number of other people that the subject believed also heard the fit. By the assistant’s comments before the experiment, and also by the number of voices heard to speak in the first round of the group discussion, the subject was led to believe that the discussion group was one of three sizes: either a two-person group (consisting of a person who would later have a fit and the real subject), a three-person group (consisting of the victim, the real subject, and one confederate voice), or a six-person group (consisting of the victim, the real subject, and four confederate voices). All the confederates’ voices were tape-recorded.
VARIATIONS IN GROUP COMPOSITION
Varying the kind as well as the number of bystanders present at an emergency should also vary the amount of responsibility felt by any single bystander. To test this, several variations of the three-person group were run. In one three-person condition, the taped bystander voice was that of a female, in another a male, and in the third a male who said that he was a premedical student who occasionally worked in the emergency wards at Bellevue hospital.
In the above conditions, the subjects were female college
students. In a final condition males drawn from the same introductory
psychology subject pool were tested in a three-person female-
bystander condition.
TIME TO HELP
The major dependent variable was the time elapsed from the start of the victim’s fit until the subject left her experimental cubicle. When the subject left her room, she saw the experimental assistant seated at the end of the hall, and invariably went to the assistant. If 6 minutes elapsed without the subject having emerged from her room, the experiment was terminated.
As soon as the subject reported the emergency, or after 6 minutes had elapsed, the experimental assistant disclosed the true nature of the experiment, and dealt with any emotions aroused in the subject. Finally the subject filled out a questionnaire concerning her thoughts and feelings during the emergency, and completed scales of Machiavellianism, anomie, and authoritarianism (Christie, 1964), a social desirability scale (Crowne & Marlowe, 1964), a social responsibility scale (Daniels & Berkowitz, 1964), and reported vital statistics and socioeconomic data.
Results
PLAUSIBILITY OF MANIPULATION
Judging by the subjects’ nervousness when they reported the fit to the experimenter, by their surprise when they discovered that the fit was simulated, and by comments they made during the fit (when they thought their microphones were off), one can conclude that almost all of the subjects perceived the fit as real. There were two exceptions in different experimental conditions, and the data for these subjects were dropped from the analysis.
EFFECT OF GROUP SIZE ON HELPING
The number of bystanders that the subject perceived to be present had a major effect on the likelihood with which she would report the emergency (Table 1). Eighty-five percent of the subjects who thought they alone knew of the victim’s plight reported the seizure before the victim was cut off, only 31% of those who thought four other by-standers were present did so.
TABLE 1
|
GROUP SIZE
|
N
|
% RESPONDING
|
TIME IN SEC.
|
SPEED SCORE
|
|---|---|---|---|---|
| 2 (S & victim) | 13 | 85 | 52 | .87 |
| 3 (S, victim, & 1 other) | 26 | 62 | 93 | .72 |
| 6 (S, victim, & 4 others) | 13 | 31 | 166 | .51 |
Note.–p value of differences: x257.91, p,.02; F58.09, p,.01, for speed scores.
Every one of the subjects in the two-person groups, but only
62% of the subjects in the six-
person groups, ever reported the emergency. The cumulative
distributions of response times for groups of different perceived
size (Figure 1) indicates that, by any point in time,
more subjects from the two-person groups had responded than
from the three-person groups, and more from the three-person
groups than from the six-person groups.
FIGURE 1
Cumulative distributions of helping responses.
Ninety-five percent of all the subjects who ever responded did so within the first half of the time available to them. No subject who had not reported within 3 minutes after the fit ever did so. The shape of these distributions suggest that had the experiment been allowed to run for a considerably longer time, few additional subjects would have responded.
SPEED OF RESPONSE
To achieve a more detailed analysis of the results, each subject’s time score was transformed into a "speed" score by taking the reciprocal of the response time in seconds and multiplying by 100. The effect of this transformation was to deemphasize differences between longer time scores, thus reducing the contribution to the results of the arbitrary 6-minute limit on scores. A high speed score indicates a fast response.
An analysis of variance indicates that the effect of group size is highly significant (p,.01). Duncan multiple-range tests indicate that all but the two- and three-person groups differ significantly from one another (p,.05).
VICTIM’S LIKELIHOOD OF BEING HELPED
An individual subject is less likely to respond if he thinks that others are present. But what of the victim? Is the inhibition of the response of each individual strong enough to counteract the fact that with five onlookers there are five times as many people available to help? From the data of this experiment, it is possible mathematically to create hypothetical groups with one, two, or five observers.2 The calculations indicate that the victim is about equally likely to get help from one bystander as from two. The victim is considerably more likely to have gotten help from one or two observers than from five during the first minute of the fit. For instance, by 45 seconds after the start of the fit, the victim’s chances of having been helped by the single bystanders were about 50%, compared to none in the five observer condition. After the first minute, the likelihood of getting help from at least one person is high in all three conditions.
EFFECT OF GROUP COMPOSITION ON HELPING THE VICTIM
Several variations of the three-person group were run. In one pair of variations, the female subject thought the other bystander was either male or female; in another, she thought the other bystander was a premedical student who worked in an emergency ward at Bellevue hospital. As Table 2 shows, the variations in sex and medical competence of the other bystander had no important or detectable affect on speed of response. Subjects responded equally frequently and fast whether the other bystander was female, male, or medically experienced.
SEX OF THE SUBJECT AND SPEED OF RESPONSE
Coping with emergencies is often thought to be the duty of males, especially when females are present, but there was no evidence that this was the case in this study. Male subjects responded to the emergency with almost exactly the same speed as did females (Table 2).
TABLE 2
|
GROUP SIZE
|
N
|
% RESPONDING |
TIME IN SEC.
|
SPEED SCORE
|
|---|---|---|---|---|
| Female S, male other | 13 | 62 | 94 | 74 |
| Female S, female other | 13 | 62 | 92 | 71 |
| Female S, male medic other | 5 | 100 | 60 | 77 |
| Male S, female other | 13 | 69 | 110 | 68 |
aThree-person group, male victim.
REASONS FOR INTERVENTION OR NONINTERVENTION
After the debriefing at the end of the experiment each subject was given a 15-item checklist and asked to check those thoughts which had "crossed your mind when you heard Subject 1 calling for help." Whatever the condition, each subject checked very few thoughts, and there were no significant differences in number or kind of thoughts in the different experimental groups. The only thoughts checked by more than a few subjects were "I didn’t know what to do" (18 out of 65 subjects), "I thought it must be some sort of fake" (20 out of 65), and "I didn’t know exactly what was happening" (26 out of 65).
It is possible that subjects were ashamed to report socially undesirable rationalizations, or, since the subjects checked the list after the true nature of the experiment had been explained to them, their memories might have been blurred. It is our impression, however, that most subjects checked few reasons because they had few coherent thoughts during the fit.
We asked all subjects whether the presence or absence of other bystanders had entered their minds during the time that they were hearing the fit. Subjects in the three- and six-person groups reported that they were aware that other people were present, but they felt that this made no difference to their own behavior.
INDIVIDUAL DIFFERENCE CORRELATES OF SPEED OF REPORT
The correlations between speed of report and various individual differences on the personality and background measures were obtained by normalizing the distribution of report speeds within each experimental condition and pooling these scores across all conditions (n562—65). Personality measures showed no important or significant correlations with speed of reporting the emergency. In fact, only one of the 16 individual difference measures, the size of the community in which the subject grew up, correlated (r52.26, p,.05) with the speed of helping.
Discussion
Subjects, whether or not they intervened, believed the fit to be genuine and serious. "My God, he’s having a fit," many subjects said to themselves (and were overheard via their microphones) at the onset of the fit. Others gasped or simply said "Oh." Several of the male subjects swore. One subject said to herself, "It’s just my kind of luck, something has to happen to me!" Several subjects spoke aloud of their confusion about what course of action to take, "Oh God, what should I do?"
When those subjects who intervened stepped out of their rooms, they found the experimental assistant down the hall. With some uncertainty, but without panic, they reported the situation. "Hey, I think Number 1 is very sick. He’s having a fit or something." After ostensibly checking on the situation, the experimenter returned to report that "everything is under control." The subjects accepted these assurances with obvious relief.
Subjects who failed to report the emergency showed few signs of the apathy and indifference thought to characterize "unresponsive bystanders." When the experimenter entered her room to terminate the situation, the subject often asked if the victim was "all right." "Is he being taken care of?" "He’s all right isn’t he?" Many of these subjects showed physical signs of nervousness; they often had trembling hands and sweating palms. If anything, they seemed more emotionally aroused than did the subjects who reported the emergency.
Why, then, didn’t they respond? It is our impression that nonintervening subjects had not decided not to respond. Rather they were still in a state of indecision and conflict concerning whether to respond or not. The emotional behavior of these nonresponding subjects was a sign of their continuing conflict, a conflict that other subjects resolved by responding.
The fit created a conflict situation of the avoidance-avoidance type. On the one hand, subjects worried about the guilt and shame they would feel if they did not help the person in distress. On the other hand, they were concerned not to make fools of themselves by overreacting, not to ruin the ongoing experiment by leaving their intercom, and not to destroy the anonymous nature of the situation which the experimenter had earlier stressed as important. For subjects in the two-person condition, the obvious distress of the victim and his need for help were so important that their conflict was easily resolved. For the subjects who knew there were other bystanders present, the cost of not helping was reduced and the conflict they were in more acute. Caught between the two negative alternatives of letting the victim continue to suffer or the costs of rushing in to help, the nonresponding bystanders vacillated between them rather than choosing not to respond. This distinction may be academic for the victim, since he got no help in either case, but it is an extremely important one for arriving at an understanding of the causes of bystanders’ failures to help.
Although the subjects experienced stress and conflict during the experiment, their general reactions to it were highly positive. On a questionnaire administered after the experimenter had discussed the nature and purpose of the experiment, every single subject found the experiment either "interesting" or "very interesting" and was willing to participate in similar experiments in the future. All subjects felt they understood what the experiment was about and indicated that they thought the deceptions were necessary and justified. All but one felt they were better informed about the nature of psychological research in general.
Male subjects reported the emergency no faster than did females. These results (or lack of them) seem to conflict with the Berkowitz, Klanderman, and Harris (1964) finding that males tend to assume more responsibility and take more initiative than females in giving help to dependent others. Also, females reacted equally fast when the other bystander was another female, a male, or even a person practiced in dealing with medical emergencies. The ineffectiveness of these manipulations of group composition cannot be explained by general insensitivity of the speed measure, since the group-size variable had a marked effect on report speed.
It might be helpful in understanding this lack of difference to distinguish two general classes of intervention in emergency situations: direct and reportorial. Direct intervention (breaking up a fight, extinguishing a fire, swimming out to save a drowner) often requires skill, knowledge, or physical power. It may involve danger. American cultural norms and Berkowitz’s results seem to suggest that males are more responsible than females for this kind of direct intervention.
A second way of dealing with an emergency is to report it to someone qualified to handle it, such as the police. For this kind of intervention, there seem to be no norms requiring male action. In the present study, subjects clearly intended to report the emergency rather than take direct action. For such indirect intervention, sex or medical competence does not appear to affect one’s qualifications or responsibilities. Anybody, male or female, medically trained or not, can find the experimenter.
In this study, no subject was able to tell how the other subjects reacted to the fit. (Indeed, there were no other subjects actually present.) The effects of group size on speed of helping, therefore, are due simply to the perceived presence of others rather than to the influence of their actions. This means that the experimental situation is unlike emergencies, such as a fire, in which bystanders interact with each other. It is, however, similar to emergencies, such as the Genovese murder, in which spectators knew others were also watching but were prevented by walls between them from communication that might have counteracted the diffusion of responsibility.
The present results create serious difficulties for one class of commonly given explanations for the failure of bystanders to intervene in actual emergencies, those involving apathy or indifference. These explanations generally assert that people who fail to intervene are somehow different in kind from the rest of us, that they are "alienated by industrialization," "dehumanized by urbanization," "depersonalized by living in the cold society," or "psychopaths." These explanations serve a dual function for people who adopt them. First, they explain (if only in a nominal way) the puzzling and frightening problem of why people watch others die. Second, they give individuals reason to deny that they too might fail to help in a similar situation.
The results of this experiment seem to indicate that such personality variables may not be as important as these explanations suggest. Alienation, Machiavellianism, acceptance of social responsibility, need for approval, and authoritarianism are often cited in these explanations. Yet they did not predict the speed or likelihood of help. In sharp contrast, the perceived number of bystanders did. The explanation of bystander "apathy" may lie more in the bystander’s response to other observers than in presumed personality deficiencies of "apathetic" individuals. Although this realization may force us to face the guilt-provoking possibility that we too might fail to intervene, it also suggests that individuals are not, of necessity, "noninterveners" because of their personalities. If people understand the situational forces that can make them hesitate to intervene, they may better overcome them.
Notes
1To test whether the order in which the subjects spoke in the first discussion round significantly affected the subjects’ speed of report, the order in which the subjects spoke was varied (in the six-person group). This had no significant or noticeable effect on the speed of the subjects’ reports.
2The formula for the probability that at least one person will help by a given time is 1 - (1 - P) n where n is the number of observers and P is the probability of a single individual (who thinks he is one of n observers) helping by that time.
References
1. Aronfreed, J. The origin of self-criticism. Psychological Review, 1964, 71, 193—219.
2. Berkowitz, L., Klanderman, S., & Harris, R. Effects of experimenter awareness and sex of subject on reactions to dependency relationships. Sociometry, 1964, 27, 327—329.
3. Christie, R. The prevalence of machiavellian orientations. Paper presented at the meeting of the American Psychological Association, Los Angeles, 1964.
4. Crowne, D., & Marlowe, D. The approval motive. New York: Wiley, 1964.
5. Daniels, L., & Berkowitz, L. Liking and response to dependency relationships. Human Relations, 1963, 16, 141—148.
6. Milgram, S., & Hollander, P. Murder they heard. Nation, 1964, 198, 602—604.
7. Miller, N., & Dollard, J. Social learning and imitation. New Haven: Yale University Press, 1941.
8. Rosenthal, A. M. Thirty-eight witnesses. New York: McGraw-Hill, 1964.
9. Whiting, J. W. M., & Child, I. Child training and personality. New Haven: Yale University Press, 1953.
Questions for Reflection and Discussion:
1. What kind of emergency situation did Darley and Latané construct to study the bystander effect?
2. How did the researchers determine that subjects in their experiment believed that the emergency (the fit) was real and not feigned?
3. Reporting the (apparent) emergency to an experimental assistant was the operational definition of helping in the Darley and Latané study. Do you believe that this behavior is comparable to calling the police to report the attack on Kitty Genovese? Why or why not?
4. What reasons were given by "bystanders"–that is, by people who did not try to help the person apparently having the fit? Do they sound believable? How do they fit in with the researchers’ conclusions?
5. Have you ever passed somebody lying in the street or in a doorway without seeing if you could offer help? Why?
6. Do you behave differently when you are on a crowded city street or in a small town or village? How so? Why?
Source
Darley, J. M., & Latané, B. (1968). Bystander intervention in emergencies: Diffusion of responsibility. Journal of Personality and Social Psychology, 8, 377–383. Copyright © 1968 by the American Psychological Association. Reprinted with permission.
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