Social contagion is defined by Bloomer as "the relatively rapid, unwitting, non rational dissemination of a mood, impulse, form of conduct ... " [1975, p. 27]. Contagion theory thus emphasizes, and perhaps overemphasizes, the non rational aspects of collective behavior. Some factors encouraging social contagion include anonymity, personality, suggestibility, stress, and interaction amplification. ANONYMITY. At the county fair, many will meet their friends and neighbors; at the rock festival, most. will be strangers. The more anonymous the crowd, the greater t~e potential for extreme action. The anonymity of the -crowd removes the sense of individuality from the members. They do not pay attention to other members as individuals and do not feel that. they themselves are being singled out as individuals. Thus, the restraints on a member of a crowd are reduced, and one is free to indulge in behavior which would ordinarily be controlled, because moral responsibility has been shifted from the individual to the group. At least one study [Fe stinger 1952] claims to have confirmed these mechanisms through laboratory experimentation. Members of crowds seldom confess to any feeling of guilt after sharing in even the most outrageous atrocities, and this shift of moral responsibility to the group is part of the explanation. IMPERSONAL. Group behavior is typically impersonal. By this we mean that when groups interact with other groups, this interaction
takes very little account of personal feelings or personal relations between members of different groups. The soldier bears no personal grudge against the enemy soldier he shoots, nor does it matter that the opposing football player is a personal friend. At thermostatically, all cyclists may be perceived and feared as hoodlums by the locals, while, all locals may become "the enemy" .to the cyclists. The impersonality of crowd behavior
is revealed in race riots where one member of the enemy race is as good or bad as another, as this incident suggests:
We drove around for a long time. We saw a lot of colored people, but they 'were in bunches. We didn't want any of that. We wanted some guy all by himself. We saw one at Mack Avenue. Aldo drove past him and then .said, "Gimme that gun." I handed it over to him and he turned around and came back. We were about 15 feet from the man when Aldo pulled up, almost
stopped and shot. The man and we blew. We didn't know him. He wasn't bothering other people were fighting and killing and we felt like it, too. (Alfred M. Lee and Norman D. Humphrey, Race Riot, Holt, Rinehart and Winston, Inc., New York, 1943, p.,38.)
It should be no surprise that peaceful passersby are' attacked in race riots. If the other group is the enemy, then any member of the ' group .is automatically a victim, B~t if the j group setting for behavior is destroyed, -then the behavior changes. For example, in the Chicago race riot of 1919, one black man outdistanced all but one of ,his pursuers so that the two became separated from their groups and faced each other as individuals,
whereupon they quit fighting [Chicago Commission; 1922, p. 22].•Removed from their groups, they realized that fighting was pointless. Group behavior is impersonal. when interaction becomes personal, it ceases to be group behavior and changes in nature. SUGGESTIBILITY, Since crowd situations .
normally unstructured, there are' no established leaders or behavior patterns for the members. to carry out.. Furthermore, their individual responsibility has been shifted to , the 'group. Often the situation itself is confused and 'chaotic. In such a state of affairs, people sometimes act readily and uncriticallyupon suggestion, especially if the suggestion is made in a decisive, authoritative manner. The "unpredictability" of crowds is' juat another way of saying'that crowds are suggestible [Lang and Lang; 19li1, pp. 221-225]. This factor of suggestibility is, however, far from .unlimited, .and some. so geologists feel that students of crowd behavior have overemphasis- , sized its importance [Couch, 1968]. STRESS. There is considerable evidence that situation stress aids social contagion [Perry and Pugh, 1978,pp. 62-65]. In other words, people under stress -(fatigue, fear, anxiety, 'insecurity, status inconsistency, anger) are to believe rumors, to panic or join riots, mass hysteria, or social movements than people-who are calm and untroubled .
INTERACTION AMPLIFICATION, At the county fair, there IS no single "crowd" most of the time; instead, there are many small groups,often family groups; drifting about with no central focus. At the rock festival, a huge,
closelypacked crowd surrounds A single stage from whence blasts a hypnotic beat and often a countercultural message. ',Most members
lose themselves in a feeling of community and ecstasy somewhat like that of the great religious revivals of an earlier age.t This emotional buildup which crowd members give to one another is one of the most dramatic features of crowd behavior.