Leon Festinger

A Theory of Social Comparison Processes

Hypothesis I: There exists, in the human organism, a drive to evaluate his opinions and his abilities. While opinions and abilities may, at first glance, seem to be quite different things, there is a close functional tie between them. They act together in the manner in which they affect behavior. A person’s cognition (his opinions and beliefs) about the situation in which he exists and his appraisals of what he is capable of doing (his evaluation of his abilities) will together have bearing on his behavior. The holding of incorrect opinions and/or inaccurate appraisals of one’s abilities can be punishing or even fatal in many situations. It is necessary, before we proceed, to clarify the distinction between opinions and evaluations of abilities since at first glance it may seem that one’s evaluation of one’s own ability is an opinion about it. Abilities are of course manifested only through performance which is assumed to depend upon the particular ability. The clarity of the manifestation or performance can vary from instances where there is no clear ordering criterion of the ability to instances where the performance which reflects the ability can be clearly ordered. In the former case, the evaluation of the ability does function like other opinions which are not directly testable in “objective reality’. For example, a person’s evaluation of his ability to write poetry will depend to a large extent on the opinions which others have of his ability to write poetry. In cases where the criterion is unambiguous and can be clearly ordered, this furnishes an objective reality for the evaluation of one’s ability so that it depends less on the opinions of other persons and depends more on actual comparison of one’s performance with the performance of others. Thus, if a person evaluates his running ability, he will do so by comparing his time to run some distance with the times that other persons have taken. In the following pages, when we talk about evaluating an ability, we shall mean specifically the evaluation of that ability in situations where the performance is unambiguous and is known. Most situations in real life will, of course, present situations which are a mixture of opinion and ability evaluation. In a previous article (7) the author posited the existence of a drive to determine whether or not one’s opinions were “correct”. We are here stating that this same drive also produces behavior in people oriented toward obtaining an accurate appraisal of their abilities. The behavioral implication of the existence of such a drive is that we would expect to observe behaviour on the part of persons which enables them to ascertain whether or not their opinions are correct and also behavior which enables them accurately to evaluate their abilities. It is consequently

The significance of difference between means without reference to the frequency distribution function.

Most existing tests for significance of difference between means require specific assumptions concerning the distribution function in the parent population. The need for a test which can be applied without making any such assumption is stressed. Such a statistical test is derived. The application of the test involves converting scores to rank orders. The exact probabilities may then be calculated for specified differences between samples by means of which the null hypothesis may be tested. The application of the test is simple and requires a minimum of calculation. The test loses in precision because of the conversion to rank orders but gains in generality since it may be safely used with any kind of distribution.

Eye movements and decrement in the Müller-Lyer illusion

Two experiments are reported in which a decrement in the magnitude of the Müller-Lyer illusion was found if free eye movements were allowed. Little or no decrement was obtained if Ss fixated one point of the figure during inspection. In one experiment eye movements were recorded. Saccades across the perceptually short side of the Muller-Lyer figure were found to be shorter than across the perceptually long side. After inspection with free eye movements, the saccades became more nearly equal on the two sides. Such changes in eye movements did not occur if Ss fixated one point during the inspection period. The data are interpreted in terms of perception being determined by the efferent readiness activated by visual input. According to this interpretation, the decrement in the magnitude of the illusion results from recalibration of the efferent programs.

Some observations concerning saccadic eye movements

Abstract Eye movements, made in response to a target that was displaced twice (pulse-step stimuli), were recorded for three observers in order to ascertain the characteristics of the saccadic control system. Five types of pulse-step stimuli were randomly presented to the observers. The results indicate that observers did not always respond to the initial displacement of the target, but sometimes responded only to the targets final position. The percentage of instances in which observers responded to the pulse increased as the duration of the pulse increased from 50 to 200 msec. In those instances when observers responded to both target displacements, the latency of the second saccade was shorter than that of the first. When observera only responded to the targets final position, the latency of the saccade was shorter if the targets final position was in the same direction than if it was in the opposite direction from its initial displacement. These results suggest that there is continuous input of information into the saccadic control system.

Visual perception during smooth pursuit eye movements

Abstract With accurate measurement of eye position during smooth tracking, comparison of the retinal and perceived paths of spots of light moving in harmonic motion indicates little compensation for smooth pursuit eye movements by the perceptual system. The data suggest that during smooth pursuit, the perceptual system has access to information about direction of tracking, and assumes a relatively low speed, almost irrespective of the actual speed of the eye. It appears, then, that the specification of innervation to the extraocular muscles for smooth tracking is predominantly peripheral, i.e. it occurs beyond the stage in the efferent command process monitored by perception.

The perception of color with achromatic stimulation.

Abstract A series of experiments demonstrated that the flicker colors can be produced by appropriate changes in the intensity of a stationary light source. If the intensity changes resemble those produced by a Benham Top, then lateral inhibitory effects from a flickering background must be present to produce the colors. Patterns of temporal intensity changes were discovered by means of which the flicker colors were produced with a constant background.

A statistical test for means of samples from skew populations

This paper presents a test for determining significance of differences between means of samples which are drawn from positively skewed populations, more specifically, those having a Pearson Type III distribution function. The quantity 2npxg/xp (wherep equals the mean squared divided by the variance andn is the number of cases in the sample), which distributes itself as Chi Square for 2np degrees of freedom, may be referred to the tables of Chi Square for testing hypotheses about the value of the true mean. For two independent samples, the larger mean divided by the smaller mean, which distributes itself asF for 2n1p1 and 2n2p2 degrees of freedom, may be referred to theF distribution tables for testing significance of difference between means. The test assumes that the range of possible scores is from zero to infinity. When a lower theoretical score limit (c) exists which is not zero, the quantity (Mean —c) should be used instead of the mean in all calculations.

An exact test of significance for means of samples drawn from populations with an exponential frequency distribution

The mathematical derivation of a test for determining the fiducial limits of, and significance of difference between, means when the samples are drawn from exponential populations is presented. The test for differences between means takes the particularly simple form of theF test (the ratio of the larger to the smaller mean) with each mean possessed of 2n degrees of freedom,n being the number of cases in the sample. Random sampling, a range of scores upwards from a lower limit of zero, and independence of means from each other are necessary assumptions for the use of the test. Examples of situations in which the test should be used are given, together with a description of the necessary computational procedures. Comparisons of the results of the application of this test with the erroneous application of the critical ratio on actual data show that rather large discrepancies exist between the two tests. Results obtained by applying tests which assume normality to exponential distributions are subject to much error.

Interaction of perceptually monitored and unmonitored efferent commands for smooth pursuit eye movements

Abstract When observers tracked a horizontally moving spot, the path of a second spot moving at an angle to the horizontal was radically misperceived. At a signal observers abruptly switched to tracking the second spot, which was then stabilized foveally. Data concerning resulting eye movements and perceptions support a distinction between the “central” motor command, which is found to be formulated solely from the erroneous perception, and the motor command that finally reaches the eye, which, under some specifiable circumstances, has been “peripherally” transformed so that the actual motion of the eye is appropriate to the actual motion of the target.

Retinal image smear as a source of information about magnitude of eye movement.

A number of experiments were conducted to determine to what extent retinal image smearing during saccades provides information about the eye movement magnitude to the perceptual system. The technique involved obtaining measures of perceived movement when the total visual field was displaced in conjunction with saccadic eye movements. Trials with normal retinal smear were compared with trials on which smearing was greatly reduced or eliminated. The results are interpreted as showing that the absence of normal retinal smear during a saccade increases the uncertainty in the information available to the perceptual system and that this uncertainty results in a tendency to perceive smaller than veridical amounts of movement.