Social impact theory

• Social Impact Theory is the idea that people are influenced by others around them, with larger groups having more influence than smaller ones.
• The size principle states that large groups have greater power to influence behavior compared to small groups or individuals.
• The proximity principle suggests that those who are physically closer will exert stronger influences on our behavior.
• The similarity principle proposes that we tend to be most affected by those who share similar characteristics as ourselves.
• The immediacy principle argues that immediate effects from an event can lead to long-term changes in attitudes and behaviors.
• Social impact theory equation I = f(SIN)
• Multiplicative Effect:

  Latané explains how increasing the strength, immediacy and number of sources can

  significantly increase the social impact.
• Diffusion of responsibility: A person is less

  likely to take responsibility for an action in the

  presence of a group
• Bystander effect – where individuals do not

  offer help to a victim when other people are

  present
• The theory assumes obedience is dependent upon the strength, immediacy, and number of social

  sources acting on a target individual. Impact = f(SIN)
• Social impact theory proposes that obedience would be greater when the source is more immediate (I)

  and there are fewer or no barriers
• Sedikides and Jackson : Investigated in a field experiment at New York Zoo how obedient visitors

  would be when told not to lean on the railings. Strength - The found

  obedience declined from 58% when a ‘zoo keeper’ gave order compared with

  35% when dressed as an ordinary person. Immediacy - Obedience was 61%

  when the person was in the same room as the visitors and only 7% when the

  visitors went into an adjacent room. Divisional effect was tested on different

  group sizes. 1 or 2 visitors showed 60% obedience compared with only 14%

  when there were 5 or 6 visitors in a group.
• Hofling et al (1966) : Hospital field study found that nurses were prepared to follow orders on the

  phone from a confederate Doctor to administer an overdose of a drug to

  patients which were not on an approved list. Nurses should not have taken an

  order over the ‘phone nor administered a drug that was not on their ‘list’.

  95% of nurses started to administer the drug (they were prevented from doing

  so). Although the doctor was not immediately present (Immediacy was low),

  the nurses obeyed without question.
• According to social impact theory social functioning can be partly explained by looking at the functioning of individual’s but individuals can be seen as affected by the social group Individuals and when they are functioning socially. 
• • this relates to a process that influences people in a social setting. Latane said that it becomes very complex to predict the behaviour of groups as they get larger
• • Latane argues that every person is potentially a source or a target of social influence sometimes both at once 
• • Latane found that social force is determined by a combination of: Strength, Immediacy, Number
• • The likelihood someone will respond to social influence will increase with these three elements. If these three element are in place Latane suggests that the sources will influence the target
• Strength (S)

  • how much power you believe the person influencing you has and the power of the message they convey (status, authority, age, charisma)
• Immediacy (I)

  • how close the source is to the target e.g how close the group are to you at the time (proximity, close friend vs stranger(
• Number 

  • how many sources are present during the interaction e.g number of people in a group will determine human interaction 
• Multiplicative effect

  • Latane explains how increasing the strength , immediacy and number of source can significantly increase the social impact
• Law of diminishing effects

  • Latane suggested that once the source group is larger than three, each additional person has less of an influencing effect
• Divisional effects

  explains the idea that social impact is reduced if there are more targets than there are sources - the impact id divided by the number of targets and therefore the impact on each person is diminished
• Divisional effects formula

  Impact on target: f(1/SIN)
• • diffusion of responsibility
  • a person is less likely to take responsibility for an action in the presence of a group
• In a Milgram variation, he repeated the original procedure but he added to two confederates into the room with the teacher, who were ordered to refused to continue with the experiment. 

  One confederate stopped at 150v and the second at 210v. They found obedience rates drops form 65% to 10% (450v).
• However, there are validity issues with Milgram's study.

  the ecological validity is low as study was done under laboratory conditions
• Latané suggests that once the source group size (N) is larger than 3 each additional source has less influencing effect
• Agency Theory better than multiplicative formula which doesn't explain every type of obedience.


  can explain situations such as war where soldiers can follow destructive orders given by a legitimate member of authority due to autonomous state, moral strain and agentic shift
• study done by Berkowitz, Bickman and Milgram confederates stood on the pavement on a New York street, and craned their necks looking up at the building opposite

  The number of confederates was increased from 1 to15 and the impact was measured by counting the numbers of passers-by who stopped and craned their necks. They found that the effect of increasing number of confederates eventually levelled off, as the number of passers-by who stopped to look, (impact) grew smaller relative to the size of the confederate group (N).
• Latané’s social impact theory (1981) assumes obedience depends on the strength(S), immediacy(I), and number of social sources (N) acting on a target individual
• Social impact theory proposes that obedience would increase when the source is more immediate and there are few or no barriers (close I) and if the source is strong (S, e.g. high status, charismatic or has a close relationship with the target individual). The theory also suggests obedience would be greater when there are more people affecting the target individual, (N)
• Latané explains that the Multiplicative effect means that the amount of S, I and N multiply together to affect the social impact on the target. Impact = f(SIN). Therefore, as N (number of sources) increases, the impact increases e.g. causing more obedience of the targets.
• in the law of diminishing returns, Latané suggests that once the source group size (N) is larger than 3 each additional source has less influencing effect. So, an additional increase in number of sources doesn’t create a proportional increase in impact eg obedience.
• Latane (1981)

  Social impact theory can be applied to obedience but looks in general at the functioning of individuals in the presence of others, not obedience specifically.
• According to social impact theory social functioning can be partly explained by looking at the functioning of individual’s but individuals can be seen as affected by the social group. Individuals and when they are functioning socially.