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Experiment 1

Method

Subjects Subjects were 72 undergraduates from an eastern university (35 males and 37 females). [...]

Procedure Eight subjects participated in each experimental session. Subjects initially expressed their preferences among a series of paintings by Klee and Kandinsky. They were divided into two groups, allegedly on the basis of their painting preferences. Actually, group assignment was random, with the stipulation that groups were, if possible, of equal size and sex composition. [...] One of the groups (jury group) would be provided descriptions of two civil suits in which consumers had sued manufacturers of allegedly defective products. [...] The second group assumed the role of the public; that is, the second group would be asked to evaluate the jury's recommendation. [...] After a 10-minute delay (during which subjects completed an irrelevant questionnaire concerning proposed changes in course requirements), the experimenter entered each room with the recommendations from the jury group (out-group). At this point subjects were assigned to one of three conditions. Unanimous condition (n = 27). Each subject was given a sheet of paper containing the recommendations of each member of the out-group. [...] The recommendations were unanimous in both cases —all out-group members deciding for the plaintiff in Case 1 and for the defendant in Case 2. Dissent condition (n = 22). This condition was identical to the preceding one with one exception. Feedback indicated that Out-Group Member 3 dissented from the recommendations of the majority. [...] Alone condition (n = 23). The experimenter stated that often only a few members of a jury are willing to reveal their judgments. To simulate this situation, feedback from the jury would come from only one group member. [...] After receiving the out-group opinions, subjects were asked to perform another judgment task before discussing the cases among themselves. The experimenter had some money left over from a previous experiment in which he had paid subjects for their participation. This money had to -be used quickly or it reverted to the university research office; but there were insufficient funds to pay everyone. [...] Therefore, the experimenter decided to let subjects distribute the money, using a booklet of reward matrices. After completing the reward matrices, subjects were given a postexperimental questionnaire and then thoroughly debriefed.

Dependent Measures

Questionnaire measures. The first three items on the postexperimental questionnaire were 9-point bipolar scales. Subjects indicated the degree to which Person 3's behavior was due to "something about the kind of person he/she was" (dispositional causes) or to "something about the situation he/she was in" (situational causes). On the second item, subjects indicated the extent to which Person 3's behavior appeared to be a result of the influence of the other members of the out-group. The third measure required subjects to estimate how similar Person 3's behavior was to the behavior of the other out-group members. If dissent is sufficient, to individuate the out-group member, then subjects should perceive Person 3's behavior as more dispositionally caused (Item 1), less due to the influence of the others (Item 2), and more dissimilar to the others (Item 3) in the dissent condition than in the alone and unanimous conditions. [...] Finally, subjects were asked to indicate whether members of the out-group appeared to be a single group unit or a collection of unrelated individuals. [...]

Discrimination measures. Subjects were presented with six versions of a reward matrix [...]. Subjects divided rewards between two in-group members on two matrices, between two out-group members on two matrices, and between a member of the in-group and a member of the out-group on the two remaining matrices. [...]

Experiment 2

Subjects were divided into two groups, performed a group task, and received a negative evaluation of their performance from the out-group. [...] Later, subjects requested assistance from the out-group on a different task. In the cooperative condition, the out-group complied with the request; in the uncooperative condition, the out-group refused. In the partially cooperative-group condition, half of the out-group complied as a single unit. Finally, in the partially cooperative - individual condition, half of the out-group members complied as individuals. [...]

Method

Subjects Subjects were 67 males and 73 females enrolled in introductory psychology classes at an eastern university. [...]

Procedure Ten subjects participated in each experimental session. Subjects were informed that the purpose of the experiment was to explore the effect of group size on communication patterns. They would be divided into groups and asked to work on a set of problem-solving tasks. As an incentive for good performance, the experimenters were offering a cash bonus to the two groups in the session that performed best on the tasks. The number of correctly solved problems would be summed for the two groups in each experimental session. The two groups in the session that had achieved the highest total score would receive a cash bonus of $30. [...] The experimenter divided subjects into two groups (equal number of each sex when possible) in an apparently random manner. [...] Subjects in both groups were told that they were "Group A" and that the other was "Group B." Finally, subjects were informed that they might not have sufficient information to complete some of the tasks, in which case they could seek assistance from the other group by sending a written message to Group B. [...] The first task was a fairly difficult problem with 13 possible solutions. [...] The second task was a fairly simple problem that took subjects about 4 minutes to solve. The experimenter returned in 4 minutes and, if necessary, waited until the group had solved Task 2. [...] The final task consisted of a paragraph followed by seven questions. Each subject was given a copy of the passage with several phrases deleted. Upon comparing one another's version of the paragraph, subjects discovered that they did not have a complete passage; therefore, they would have to ask Group B for assistance in answering the questions. As intended, all groups sent a request for aid to Group B. [...] The experimenters never prompted the subjects to send a message. [...] The experimenter returned in 3 minutes with Group B's alleged response. At this point each group of subjects was randomly assigned to one of the following four conditions: Cooperative (n = 6 groups). The message from the out-group was written on a single sheet of paper. [...] Uncooperative (n = 6 groups). The members of Group B collectively refused to help, saying that they did not wish to spare the time from their task. Partially cooperative - group (n = 7 groups). The message contained half of the requested information [...]. Partially cooperative - individual (n = 7 groups). The experimenter returned with separate messages from each member of Group B. He stated that the group had decided to let each member choose whether or not to help. As in the preceding condition, half of the messages contained some of the requested information and half contained refusals to help. [...] Then they completed the dependent measures and were thoroughly debriefed. [...]

Dependent Measures As a manipulation check, subjects indicated how much help they had received from the out-group. Endpoints were labeled "none" and "as much as requested" on a 9-point scale. [...] Finally, subjects were asked to indicate how they would divide the $30 prize between their group (Group A) and the outgroup (Group B) if the two groups earned the bonus. [...]

Experiment 3

Method

Subjects Subjects were 90 students (35 males and 55 females) from an eastern university. [...]

Procedure The procedure and stimuli of Experiment 2 were employed in this study. Groups of subjects were randomly assigned to one of the following three conditions (n = 6 groups per condition): Individual and group conditions. These two conditions were identical to the partially cooperative - individual and partially cooperative - group conditions, respectively, of Experiment 2.

Group+ condition. Subjects were treated the same as in the group condition, with one modification. Prior to receiving the partial cooperation from the out-group, the experimenter stated that the out-group had decided to let each member choose whether or not to help. This additional information was identical to that provided in the individual condition.

Dependent measures were the same as those used in Experiment 2, with one additional question. On a 9-point scale subjects indicated how tolerant they thought the out-group was of disagreement among its members. Endpoints were labeled "not tolerant at all" (1) and "very tolerant" (9).