Social Impact Theory of Obedience (Edexcel A-Level Psychology): Revision Notes
Social Impact Theory of Obedience
Introduction
In 1981, Bibb Latané developed a comprehensive framework to explain social influence and obedience. His social impact theory proposes that people are influenced by others through various mechanisms including persuasion, inhibition, threat and support. The central concept is that of social impact, which describes how the presence and actions of other people, whether physically present or simply imagined, affect our feelings and behaviour.
Latané distinguished between two roles in social influence situations:
- The target is the individual receiving the influence
- The source represents the person or people exerting that influence
The theory provides a mathematical formulation to predict the degree of social influence in different situations. Although originally developed to explain social influence generally (including conformity and bystander behaviour), the principles can effectively explain obedience to authority.
Principles
Social forces
The theory proposes that social impact operates through three key factors: strength, immediacy and number. These components work together to determine how much influence a source will have over a target.
Strength refers to the power, status or authority held by the source relative to the target. In obedience scenarios, authority figures possess greater strength due to their perceived legitimacy, expertise or position in a hierarchy. For example, a police officer has more strength than an ordinary citizen due to their role and status. Age can also contribute to strength, with older individuals sometimes carrying more influence.
Immediacy describes the closeness between source and target, both in physical space and time. The more immediate the source (i.e., the closer in proximity), the greater their potential impact. However, immediacy can be reduced by buffers - barriers that create psychological or physical distance between source and target. In obedience contexts, authority figures who are physically present and monitoring the target will exert stronger influence than those who are distant or communicating indirectly.
Number refers to how many sources and targets exist in the social situation. When multiple sources act together to influence a single target, their combined impact increases. Conversely, when multiple targets are present, the impact of the source becomes distributed among them.
For obedience to occur, the theory suggests that authority figures must be perceived as:
- Legitimate (high strength)
- Physically or psychologically close to the individual (high immediacy)
- Ideally outnumber those being influenced (high number)
When all three factors align, obedience becomes highly likely.
Psychosocial law
Social impact does not increase linearly as the number of sources grows. Instead, it follows a pattern of diminishing returns, known as the psychosocial law.
The Lightbulb Analogy
Latané used the analogy of lightbulbs to illustrate this principle: the first lightbulb switched on in a dark room creates a dramatic increase in illumination. A second bulb improves the lighting further, but the change is less noticeable. As more bulbs are added, each additional one contributes progressively less to the overall brightness.
Similarly, the first authority figure has substantial impact on encouraging obedience. Additional authority figures increase obedience levels, but each subsequent person adds less influence than the previous one. This explains why having two authority figures is not twice as effective as having one.
Empirical Demonstration: Berkowitz, Bickman and Milgram (1969)
This field experiment at City University of New York provided evidence for the psychosocial law:
Method: Researchers arranged for varying numbers of confederates (between 1 and 15) to stand on a street and crane their necks upward, looking at the sixth floor of a university building. Stanley Milgram filmed the scene from a sixth-floor window whilst other researchers observed passers-by at ground level, recording how many stopped and imitated the behaviour by looking up.
Findings: The results confirmed the psychosocial law - whilst increasing the number of confederates did increase the number of passers-by who stopped and looked up, the effect levelled off. Each additional confederate produced a smaller increase in compliance than the previous one, demonstrating diminishing returns as group size grew.
Multiplication versus division of impact
The theory distinguishes between two opposing effects on social impact. Multiplicative effects occur when strength, immediacy and number work together to amplify influence on a target. When an authority figure possesses high status (strength), is physically close (immediacy), and is supported by others (number), their combined impact on a single target is substantial.
However, social impact can also be divided. The divisional effect occurs when influence is distributed across multiple targets rather than focused on one individual. Consider a speaker addressing a large audience: their ability to persuade any single listener is diminished because their impact is shared among many people. Each audience member receives only a fraction of the total influence.
Bystander Behaviour and Division of Impact: Latané and Darley (1970)
Latané and Darley explored the divisional effect through studies on bystander behaviour:
Finding: An individual alone was more likely to help someone in need compared to when they were part of a group. The presence of other potential helpers created a division of responsibility - the social pressure to help was distributed across all bystanders rather than concentrated on one person.
Application to obedience: This suggests that an authority figure would have reduced capacity to secure obedience from any single individual if attempting to influence multiple people simultaneously, particularly if those individuals form an alliance.
Division of Impact in Milgram's Research
Milgram's own research provides supporting evidence for the divisional effect in obedience:
Variation: Two peers (confederates) were present alongside the genuine participant, and both openly rebelled against the experimenter's instructions to administer electric shocks.
Result: When the authority figure's influence was opposed by these allied peers, obedience dropped dramatically to just 10%. This demonstrates how the presence of allies divides and weakens the impact of a source across multiple targets.
Evaluation
Strengths
Social impact theory offers several advantages as an explanation of obedience.
The theory is quantifiable - its mathematical formulation using strength, immediacy and number allows researchers to observe and measure these variables in real social situations. Studies by Asch (on conformity), Milgram (on obedience) and Latané himself (on bystander behaviour) have all demonstrated that these principles operate in observable human behaviour, lending the theory empirical support.
The theory provides a general framework that can predict behaviour under specific conditions. Rather than simply describing what happens, it explains the circumstances under which people are more or less likely to be influenced by others. This makes it useful for understanding various forms of social influence beyond just obedience.
The model is descriptive and predictive: it describes the conditions that make obedience more likely and can predict levels of obedience based on the configuration of strength, immediacy and number in a given situation. This practical utility gives the theory value in real-world applications.
Weaknesses
Despite its strengths, social impact theory has important limitations.
The theory presents individuals as passive receivers of social influence, failing to acknowledge that people actively engage with social situations. It oversimplifies human interaction by ignoring individual differences - some people are naturally more resistant to social influence whilst others are more compliant. The theory treats all targets as equivalent, when in reality everyone brings different personalities, experiences and motivations to social situations.
Static Nature of the Theory
The model is static rather than dynamic. It does not account for how the relationship between source and target might evolve during their interaction. In real obedience scenarios, targets may initially comply but then question or resist as circumstances change. The theory provides no mechanism for understanding these temporal dynamics or reciprocal influences between parties.
The theory's limited scope becomes apparent in certain situations. It cannot predict outcomes when two equal groups attempt to influence each other simultaneously. For instance, at a football match, two sets of supporters might be equal in number, strength and immediacy. The theory provides no clear prediction about which group would exert more influence on the other, or whether the principles would even apply in such contexts.
Finally, whilst the theory is descriptive and can predict when obedience is likely, it is more descriptive than explanatory. It specifies the conditions under which influence occurs but does not fully explain why people are influenced by others beyond stating that certain factors are present. It describes what happens without providing deep psychological mechanisms to explain the underlying processes.
Key Points to Remember
- Social impact theory (Latané, 1981) explains obedience through three multiplicative factors: strength (power/authority), immediacy (closeness) and number (how many sources vs targets)
- The psychosocial law shows diminishing returns - each additional source adds less impact than the previous one, similar to lightbulbs in a dark room
- Social impact can be divided when distributed across multiple targets, reducing the influence on any single individual (demonstrated when peers rebel together in Milgram's variations)
- Strengths: The theory is quantifiable, supported by empirical research, and can predict obedience levels under different conditions
- Weaknesses: Treats people as passive, ignores individual differences, is static rather than dynamic, and is limited in scope for certain social situations