personality impression formation in a maximizing difference game

Personality Impression Formation in a Maximizing Difference GameAuthor(s): Philip S. GalloSource: The Journal of Conflict Resolution, Vol. 13, No. 1 (Mar., 1969), pp. 118-122Published by: Sage Publications, Inc.Stable URL: http://www.jstor.org/stable/173303 .

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Personality impression formation in a Maximizing Difference game' PHILIP S. GALLO Department of Psychology, San Diego State College

Introduction Investigators interested in behavior in the

Prisoner's Dilemma game situation have focused a good deal of attention on the effects of sending the subjects "pro- grammed" strategies. The subject, while believing that he is playing against another subject, is actually playing against a strategy selected by the experimenter. Becker and McClintock (1967) have summarized the findings of such studies by noting that, at best, such strategies have a small effect upon the behavior of the players.

These experiments have, for the most part, employed a standard Prisoner's Di- lemma matrix. However, McClintock and Messick (1965) have suggested that a re- laxed version of the Prisoner's Dilemma game, known as the Maximizing Difference game, may be more sensitive to factors which could induce greater cooperation. A Maximizing Difference matrix is shown in Figure 1. This matrix has the advantage of establishing a unitary motive for the competitive response, i.e., the desire to maximize the difference between one's own payoff and that of one's opponent.

Gallo (1966), using a Maximizing Differ- ence matrix, compared the results of fair games, random strategies of from 80 to 100

1 This study was supported by research grant GS 1467 from the National Science Foundation to the author.

percent cooperation, and two delayed matching strategies. Both delayed matching strategies involved sending the players the response that they had made on the previous trial. They differed only in that one group of subjects received a cooperative response on trial 1, whereas another group received a competitive response on trial 1. The subjects who played a fair game and the subjects who received random cooperative strategies both averaged about 49 percent cooperative responses. The two delayed matching groups both averaged about 80 percent cooperative play. Furthermore, the amount of cooperative responses remained relatively stable over trials for the fair game and random strategy groups. In the two delayed matching groups, the number of cooperative responses increased significantly over trials, averaging about 68 percent in the first 25 trials and over 90 percent in the fourth and final block of 25 trials.

The unique aspects of the delayed matching strategy would seem to interact with the payoff properties of the Maximizing Difference matrix to produce the large increase in cooperative responses when this strategy is employed. The unique features of the delayed matching strategy are: (1) after trial 1, the real subject can never be "betrayed" by his "opponent," i.e., it is necessary for the real player to make a

CONFLICT RESOLUTION VOLU.M E XIII NUMBER 1



PERSONALITY IMPRESSION FORMATION 119

PLAYER 1

A B

P 6 5 L X A 6 0 Y E R

5 0

FIG. 1. A Maximizing Differences matrix.

competitive response before one is made to him; (2) a competitive response is always punished, one trial later; and (3) a cooperative response is always rewarded, one trial later. Thus this strategy prevents the subject from being betrayed or exploited and also prevents him from exploiting his opponent.

The increase in cooperativeness that is recorded when the delayed matching strategy is being used seems to indicate that a learning process is occurring. This learning process may be mediated by the information that the subject is receiving, through the choices of his "opponent," con- cerning the type of person with whom he is playing. If this assumption is true, the subject who plays against a delayed matching strategy should form a different and more favorable impression of his opponent than a subject who plays against either a real opponent or a random strategy. Fur- thermore, it could be predicted that a subject playing against a delayed matching strategy would see his "opponent" as being more like himself than would subjects who played against real opponents or random

strategies. The present experiment was designed to test these hypotheses.

Method SUBJECTS

Ninety male undergraduates from Intro- ductory Psychology courses at San Diego State College took part in the experiment. Subjects came to the laboratory in groups of two. They were then randomly assigned to play a "fair game" with their partner, to play a random strategy, or to play against a delayed matching strategy.

PROCEDURE

The subjects were seated in small, individual cubicles. Each cubicle contained a table, a chair, an intercom slave unit, a prize board, and a game box. The game box consisted of two buttons and four lights, with the matrix shown in Figure 1 super- imposed upon it. The buttons for player 1 were marked A and B, those for player 2 were marked X and Y. The instructions were read to the subjects via the intercom.

The subjects were told that they were participating in an experiment designed to discover the way in which people form first impressions of another person after receiving only minimal information about the other person. They were told that they would make a series of interdependent decisions and should use the decisions that the other person made to try to form an impression of the kind of person with whom they were interacting. It was pointed out that, after the decisions were made, they would be asked to evaluate the personality of the other person.

The game was then fully explained to the subjects, using instructions that were as neutral in tone as possible. The subjects were informed that they could exchange the points that they made for ball-point pens at the end of the experiment. The attention



120 PHILIP S. GALLO

90-

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BLOCKS OF 25 TRIALS

Fic, 2. Mean percentage of cooperative responses for the three groups, by blocks of 25 trials.

of the subjects was called to the prize board in front of each of them, which showed that they could obtain a $1.98 ball-point pen by earning 550 points, a 980 ball-point pen for 450 points, and a 290 ball-point pen for 350 points. They were told that it was possible for any combination of prizes to be obtained, ranging from top prizes for both of them to no prizes for either of them.

The subjects played a total of 100 trials. At the end of the 100 trials, the subjects filled out a semantic differential form on which they evaluated both the personality of the other player and their own. Fifteen bipolar adjectives were used for the evaluation. The subjects also filled out a brief questionnaire which asked them how interesting they had found the experiment, how

helpful their partner had been, how helpful they were to their partner, and how likable they had found their partner.

Results

Figure 2 shows the percentage of cooperative responses made by the three groups by blocks of twenty-five trials. Over all, the delayed matching subjects achieved a mean of 77.43 percent cooperative responses, the fair game subjects a mean of 68.23 percent, and the random strategy subjects a mean of 63.09 percent. Analysis of variance applied to these results yields an F of 2.68, which reaches only the .10 level of significance. A Duncan's new multiple range test indicates that the delayed matching subjects are significantly different from

CONFLICT RESOLUTION VOLUME XIII NUMBER I



PERSONALITY IMPRESSION FORMATION 121

PERSONALITY TRAITS

A~~~~~~~-N4 4,1

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FIG. 3. Mean judgments of the "other player's personality as a function of the "other person's" strategy.

the random strategy subjects at the .05 level.

Figure 3 shows the profile of the evaluations given to the "other player" as a function of the "other player's" strategy. It can be seen that on all of the adjectives but two, the delayed matching partner is given a more favorable evaluation than either the real partner or the random strategy partner. The overall evaluations given by the three groups are significantly different (F287

5.46, p < .01). Another measure of the extent to which

an individual likes his partner can be obtained by subtracting the score he gave his partner from the score he gave himself on each of the fifteen adjective pairs. This

procedure yields an average discrepancy score of -.609 for the random strategy subjects, -.497 for the fair game subjects, and -.011 for the delayed matching subjects. Analysis of variance indicates that the first two figures are significantly different from 0. The F for the delayed matching group fails to reach even the expected value of 1.

Analysis of the questionnaire data tends to indicate a similar pattern. The subjects who played against the delayed matching strategy found their partners significantly more likable and more helpful than did the subjects in the other two conditions. They did not find the experiment more interesting nor did they feel that they were more



122 PHILIP S. GALLO

helpful to their partners. In fact, the fair game subjects considered themselves to be the most helpful. The difference was not significant when compared to the delayed matching group but did reach significance when compared to the random strategy subjects.

Discussion

The results strongly indicate that a delayed matching strategy does have a significant effect upon the perceptions of the person with whom the subject believes he is playing. These subjects evaluate such a partner more favorably, both on a semantic differential and on straightforward questionnaire items, than subjects who played a real partner or a random strategy. They also tend to see such a partner as possessing the same personality traits that they attrib- ute to themselves.

It is interesting to note that there are no significant differences in the personality ratings given by people who played a real partner as compared to those who played against random strategies. This finding may account for the fact that the majority of studies comparing fair games to program- med strategies have failed to find differences in behavior as a function of strategies. Apparently, random strategies are suffi- ciently close approximations of the way in which real partners play that subjects do not respond differentially to them.

The delayed matching subjects in the

present experiment produced approximately the same amount of cooperative responses as did the delayed matching groups in the previous experiment. However, both the fair game and random strategy subjects made considerably more cooperative responses than did their counterparts in the previous experiment. A possible explanation for this finding may be the particular set of instructions used in this experiment. The subjects were told that the experiment was concerned with personality impression formation, and the game was presented merely as a task that was to be used to help them in forming the impressions. Subjects in the previous experiment were told that they were taking part in a decision-making experiment and the game was presented as the primary focus of interest. It is quite likely that imbedding the game in a larger task tends to break up whatever competitive set exists. This possibility will be explored in future research.

REFERENCES

BECKER, G. M., and C. G. MCCLINTOCK.

"Value: Behavioral Decision Theory," An- nual Review of Psychology, 18 (1967), 239- 89.

GALLO, P. S. "The Effects of Score Feedback and Strategy of the Other on Cooperative Behavior in a Maximizing Differences Game," Psychonomic Science, 5 (1966), 401-402.

MCGCLINTOCK, C. G., and D. M. MESSICK.

"Strategic and Motivational Aspects of Social Interaction." A research grant proposal sub- mitted to the National Science Foundation, 1965.

CONFLICT RESOLUTION VOLUME XIII NUMBER 1



personality impression formation in a maximizing difference game

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