The standards by which behavior is judged in a given social group; the way the members of a group are expected to think, feel or act.Social norms determine to a large extent whether we feel that our attitudes are sound and our actions appropriate. An example cited by Secord and Back- man (1964) is the set of standards implicitly or explicitly adopted by the more traditional fraternities: making moderately good grades, loyalty to the fraternity, congeniality with fraternity brothers, dating girls from certain sororities and not others, helping on fraternity projects, and believing that one’s own fraternity is the best on campus.Norms are not always ready-made affairs, as they are in this instance. We sometimes establish them in the course of our experience. Sherif (1948) has performed an ingenious experiment which shows how these frames of reference may be set up. He seated three persons in a dark room and told them that in a few moments a point of light would appear, move a short distance and then go out. The subjects were instructed to call out the number of inches they thought the light moved. The light was then turned on repeatedly at intervals, and the subjects’ judgments were recorded.The experiment produced an interesting result. Although the three subjects differed rather widely on their initial judgments, the differences tended to narrow down after a number of trials, eventually coming within an inch or two of each other. But in truth they had no real basis for judging the amount of movement, for the light was completely stationary.This experiment was based on a well- known peculiarity of perception known as the autokinetic effect. For reasons unknown, a stationary point of light in a dark room will appear to move by itself. On what basis, then, did the subjects alter their judgment? Sherif’s answer was that in the absence of clear perceptual cues upon which to base their estimates, the subjects turned to each other for guidance. Many other groups have been studied in the same general situation, and the end result has nearly always been a narrow range of judgment. This agreed-upon range then acts as a social norm.The Sherif experiment has thrown further light on group norms. When subjects who had established a norm in the group situation were tested alone, they still responded in terms of the norm. On the other hand, when subjects who had formed their norm in an individual situation were later placed in a group, they were found to change these norms gradually until they arrived at a group norm.Many investigators have sought to define the forces that bring about group norms. One important theory is that pressures toward conformity arise when “reward-cost outcomes” are likely to be adversely affected by nonconformity—that is, we feel that we lose more than we gain if we go against the group. This is especially likely to occur when group goals are involved, for the disadvantage, or cost, of nonconformity is high in such cases and the rewards of conformity are considerable. In committee work, for example, it is important to establish a rule against everyone talking at once; and when military planes are flying in formation, it is essential to have them adhere strictly to carefully defined maneuvers.The advantages of conformity are obvious in these practical matters, but far less apparent in the case of opinions and attitudes. The explanation of adherence to social norms in the latter case is that in forming our attitudes toward things and people, we rely on two sources of information—our own observations and sense experience; and the interpretations and information we get from others. The latter source, termed “social reality,” is often less certain than our observations of physical reality, since the opinions of other people differ so much. At any rate, the relative weight of the two sources varies with different circumstances. In general, we depend more on our senses in cases where we can make a direct perceptual judgment or where our information leads to an obviously correct answer; but we are prone to rely on the judgment of other persons when our sense stimuli are ambiguous or unstructured, as in the autokinetic situation. The influence of other people is particularly great when there is no perceptual reality at all against which to check our judgment and where, in addition, distinct social and emotional “rewards,” such as social acceptance, approval, and the satisfaction of belonging operate in favor of conformity. An example is adherence to the dogma of a particular religious faith.Typically, social norms develop in situations where the attitudes or actions in question would not ordinarily be adopted, for there is no need for group controls where people spontaneously adapt themselves to others. But where the situation is ambiguous or unstructured, or where individuals have a resistance against actions that are necessary to group functioning, normative processes emerge in order to provide direction or to ensure that certain behavior is carried out.The operations by which norms are communicated and enforced have been termed “norm-sending processes” (Rom- metveit, 1955). These processes comprise, first, defining the attitudes or behavior in question; second, monitoring the extent to which individuals conform to the norm; and third, applying sanctions in the form of reward or punishment for conformity or nonconformity. All these processes may be carried out in either direct or subtle ways.An adequate theory of normative behavior must answer the following questions: What determines the kinds of attitudes or behavior that become the targets for norm-sending? Why is a greater degree of conformity found in some groups than in others? What makes some members of the group more conformist than others? Attempts have been made to answer these questions in terms of four conditions emphasized by “exchange theory.” These are: (1) the degree to which group members find the behavior or attitudes of other people rewarding or costly; (2) the distribution of rewards, dependencies and alternatives that determines the power structure of the particular group;(3) the degree to which behavior in accordance with the norm is intrinsically rewarding or costly; and (4) the degree to which behavior is open to surveillance and to the imposition of sanctions.In general, it can be said that normative controls arise where individuals have become dependent upon the group for satisfaction of their needs. In such cases actions and ideas that satisfy the most powerful persons in the group are most likely to give rise to norms. Where behavior required to achieve group goals is especially costly, no group norms at all may result, or else they may be formed merely to minimize the cost or distribute it evenly throughout the group. Behavior that is hard to monitor is also less likely to be subjected to normative control.All these points can be illustrated by the single problem of controlling nuclear tests. First, the need for group norms is based on the fact that each nuclear nation is dependent on others for the achievement of peace. Second, the most powerful nations are most deeply involved in creating the necessary agreements. Third, these agreements have been hard to establish because they are costly to the nations involved, for they mean that the usual secrecy and sovereignty cannot be maintained. Fourth, these “costs” can, nevertheless, be minimized if they are shared among the different nations. Fifth, difficulties involved in monitoring nuclear activities, as well as in gaining acceptance for the principle of monitoring, have held up the process of establishing full control over these activities.