The following is an excerpt of the intervention methodology. For more information, please see the full text of the article on the publisher's website or through your institution's library.

Subjects

Four-hundred and ninety-four male and female undergraduate students [...]. Each experimental session involved mixed-sex groups of from eight to twelve subjects each.

Procedure

When a group of subjects arrived at the experimental session, they were ushered into the experimental room and seated around a large table. Subjects were told they would participate in an industrial simulation which consisted of working on a series of business-like tasks under various kinds of pressure. The subjects were told that each task must be completed within a certain time period, and that if the product of the task met specified standards, subjects would receive a monetary reward for their work. They were also told to expect to complete some reports concerning the tasks as requested periodically throughout the experiment. The experimenter than stated that since the simulation was concerned with the performance of small groups, the large group would be divided into two small ones.

Subjects drew slips of colored paper from a box and were placed in two groups based on the color of paper they drew. It was prearranged that there would be an equal number of people in each group and the groups were controlled so that similar numbers of males and females would be in each of the small groups.

Manipulation of type of group.

In the cooperative conditions, subjects were told that cooperation between groups within an industry was an important aspect of the work situation. The experimenter explained that the product of each group would be combined and only if this combined product met the standard would both groups earn the monetary prize available for the task. The subjects in the competitive condition were informed that they would be competing against each other for the reward available for each task. The experimenter stated that the products of the two groups would be compared to each other as well as to a standard [...].

In the individualistic condition, the experimenter explained that two groups had been formed simply because it was easier and faster to use two groups in one session. On the first task, subjects were told they would be given the case history of Johnny Rocco, a young boy who required psychological counseling. The group's task was to de-sign a treatment program for him.

Subjects in the cooperative condition were informed that the two programs would be combined and analyzed by a computer. In the individualistic condition, the subjects were told that if their group's program met the standard level of effectiveness, each member would receive 50¢. The groups were then led to separate rooms and given the material necessary to complete the task. After 20 min had elapsed, the solutions were collected. The groups then returned to the large outer room, where instructions for the second task were given.

Following completion of the word task, the two groups were brought together again and were given the first questionnaire. When all the subjects had completed the questionnaire, the experimenter stated that the groups would be combined and would work together as one group to produce one solution for each of the remaining tasks. Subjects were given a brief description of a toothpaste product and asked to write a slogan for it. Ten minutes were allotted for this task.

Manipulation of outcome.

Upon completion of the slogan task, the experimenter typed the slogan solution into the teletype and appeared to receive a reply almost immediately. In the success condition, the experimenter announced that the group had been successful in meeting the task requirements. In the failure condition, he simply said that the group solution had not met the standard. For the second task, subjects were given information about several trucks and truck drivers and asked to allocate the trucks to the drivers to ensure that everyone would be satisfied [...].

After the group had worked on the problem for 20 min, the experimenter typed the solution into the teletype and again announced the outcome of the task. All groups were given the same feedback that they had received on the first task in this series. Thus, each group was informed that they had either succeeded at both tasks or failed at both. Following completion of all of the tasks, the experimenter again requested that each member of the group complete a questionnaire.