Social Impact Theory

• Key Aspects:

  • SIN = Strength, Immediacy, Number
  • Psychosocial Law - Plateau effect
  • Sources Vs Targets of Influence
  • Multiplication Vs Division of Impact
  • Social Loafing
  • Group Polarisation
• Strength; the strength of the source can be determined by status, authority, age or any influential power - friends more influential than strangers
• Number; refers to the number of sources and targets there are in any given social situation
• Authority with high SIN will ensure higher levels of obedience - this has research supporting its impact on observable behaviour, as well as face validity
• Plateau effect - It isn’t the case that as S.I.N increases so does the social impact at a point any further increase does not lead to a proportionate social impact
• There are targets of social influence, and sources who exert influence; which is affected by different principles: conformity, bystander behaviour, and obedience
• Multiplication of impact - The greater the S.I.N of the source the increased influence; this does level off 
• Division of Impact - More targets to be influenced reduces the effect of the source to change behaviour, authority has less influence if the target has an ally or (allies)
• Social Loafing - The term for people who are in a group but do not contribute to the group’s decisions or actions
• Group Polarisation - The tendency for a group to have more extreme ideas and attitudes than individuals within the group - might give a group a sense of identity
• Immediacy; determined by proximity/presence of buffers/barriers between source to target - the greater distance/barriers, the less influence