Introduction to Group Dynamics
Senior 6 · Psychology (Languages)
Introduction to Group Dynamics
Lesson 2 of 4
25 min
On Halloween night in 1976, Ed Diener and colleagues watched 1,352 children who went from house to house in Seattle, in the United States, asking for sweets, as is the custom there. At 27 houses a woman greeted them, pointed to a bowl of sweets and a bowl of coins, told each child to take one sweet, and left the room. A hidden observer counted what happened next. Sometimes the woman first asked each child’s name and address; sometimes she let them stay anonymous in their costumes.
Children who were anonymous and in a group broke the rule (taking extra sweets or coins) most often: about 57% of them. Children who came alone and had given their names broke it least: about 8%. Being in a group and being unidentifiable changed behaviour more than anything about the individual children.
Definition
Group behaviour: the way people act when they are members of a group, as shaped by its norms, roles, size, cohesion, task and leadership.
Deindividuation: a state in which a person in a group feels less identifiable and less self-aware, which was once thought to release behaviour normally held back by personal standards.
Social loafing: putting in less effort when working in a group than when working alone, because individual contributions are hidden.
Cohesiveness: the strength of the forces that keep members in a group, such as liking each other, commitment to the task and pride in the group.
| Factor | How it affects behaviour |
|---|---|
| Size | Larger groups have more resources but more loafing, less participation per member and harder coordination. |
| Composition | Similar members (homogeneous) agree quickly; mixed members (heterogeneous) bring more ideas but may clash. |
| Cohesiveness | Cohesive groups communicate more and members stay; but very cohesive groups may pressure dissenters. |
| Norms | Expectations decide whether members work hard, arrive on time or share information. |
| Type of task | The task decides whose effort matters most (Steiner, below). |
| Communication network | Who can talk to whom affects speed, accuracy and satisfaction (Leavitt, below). |
| Leadership | Style of leading changes atmosphere and productivity (next lesson). |
| Culture and setting | Values such as respect for elders or for consensus shape who speaks and how decisions are made. |
Ivan Steiner (1972) classified group tasks by how members’ contributions combine:
| Task type | Group result depends on | Example |
|---|---|---|
| Additive | The sum of all members’ efforts | Pulling a fishing net or a tug of war |
| Compensatory | The average of members’ judgements | Estimating the number of beans in a sack |
| Disjunctive | The best member | Solving a riddle: one correct answer is enough |
| Conjunctive | The weakest member | A group hike that moves at the pace of the slowest walker |
| Discretionary | How the group chooses to combine efforts | Deciding how to share out a group presentation |
Social loafing is most likely in additive tasks, where any one person’s effort is hidden in the total.
In 1951 Harold Leavitt gave five-person groups a simple puzzle that could only be solved by passing written notes along fixed channels. He compared several networks:
Figure 1. In Leavitt’s study the wheel solved simple problems fastest, but only the person at the hub enjoyed it; members of the circle were slower but most satisfied. Later work found decentralised networks do better on complex problems, where the hub becomes overloaded.
Opinion Science: “Trick-or-Treating & ‘Deindividuation’ (Halloween Psychology)”. Watch for how the Halloween study was set up and how the presenter explains what anonymity really changes.
Important
Evaluate deindividuation. The Halloween study was a large field study in a natural setting, but children could not be randomly assigned to come alone or in groups. More importantly, a 1998 review of 60 studies by Tom Postmes and Russell Spears found little support for the idea that anonymity makes people generally wild. Instead, anonymous people follow the norms of the group they are in more closely. In one study (Johnson and Downing, 1979), anonymous participants dressed in robes resembling the Ku Klux Klan gave more electric shocks to a learner, but anonymous participants dressed in nurses’ uniforms gave fewer shocks. Anonymity amplifies whatever the group’s norms are, good or bad.
Warning
Don’t write that groups always perform worse than individuals. Groups beat their average member on disjunctive tasks and many complex tasks; they underperform mainly through loafing and poor coordination, which good design can reduce.
Tip
Exam technique: for “factors affecting group behaviour”, use the mnemonic SCC-NTL-C: Size, Composition, Cohesiveness, Norms, Task, Leadership, Culture, and give one example for each you use.
Practice
Sources and credits
Written by Ganzaa: the text, the tables, Figure 1 and the exercises. The photo is used unchanged. This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
