Collective behaviour is relatively unorganized, spontaneous and results from interstimulation among participants. The view that ‘mind’ of crowds replaces personal responsibility is mistaken, at least in most cases. Crowding, an aversive psychological state, is not equivalent to population density. Four models of crowding are proposed: sensory overload; density–intensity; loss of control; and attribution. Collective behaviours without interpersonal contact include fads and fashions and behavioural contagions, the rapid spread of beliefs, emotionality and behaviour throughout a crowd by means of rumour and imitation. One explanation for the antisocial behaviour contagion is deindividuation theory, a loss of personal identity leading to a lowering of normal restraints on behaviour. Conditions which contribute to deindividuation include a loss of identifiable characteristics, an arousing group activity, loss of temporal perspective and a novel situation. Mass psychogenic illness refers to the spread of a strong emotional reaction accompanied by physical symptoms with no physical cause, often triggered by some unusual event in the context of ongoing anxiety. Uncertainty, outcome relevance, personal anxiety and credibility all determine whether an individual is likely to be influenced to repeat a rumour. Fads and fashions are related to status marking, the desire of people to identify with certain groups and relief from the banality of everyday life. A social movement is a large group formed spontaneously in support of shared goals.

KEYWORDS: behavioural contagion, collective behavior, crowding, deindividuation, fads, fashions, interstimulation, psychogenic illness, rumour, social movement

1. Collective behaviour is relatively common in situations such as hockey games or on crowded buses.

2. The evidence shows that some crowd situations release undesirable human instincts.

3. Most conspiracy theories develop when authorities try to suppress the truth about events of great concern to the public.

4. Fashions often serve to distinguish people belonging to different social classes.

5. Collective behaviours in which people want to cheer a Pope, hockey team or political leader are contagions of expression.

6. Rumours in the business world have been deliberately generated to harm competitors.

7. A trade union is an example of a reform, rather than a revolutionary, social movement.

8. During the social unrest stage, social movements develop a formal ideology to guide future behaviour.

9. Cults may provide emotional support for their members.

10. The term social movement is never used in connection with religious movements.

1. F

2. F

3. F

4. T

5. T

6. T

7. T

8. F

9. T

10. F 

MCQ's for Chapter 14

1. What are the three defining characteristics of collective behaviour?

2. Describe and criticize the contagion theory of crowd behaviour.

3. What are the five conditions for deindividuation?

4. How does emergent norm theory explain crowd behaviour?

5. Discuss contagions of anxiety and give an example.

6. Discuss, with examples, the concept of mass psychogenic illness.

7. Define rumours and discuss how rumours are transmitted.

8. Describe the three social psychological processes observed in the Jonestown incident?

9. What is an urban legend? Give examples.

10. How do fads and fashions differ? 

1. Describe four factors that influence the development and transmission of rumours?

2. What are the stages in the development of a social movement?