- Email: [email protected]
Motion perception and personality. I
MOTION
PERCEPTION
AND
PERSONALITY.4
G. JOHANSSON, University
of Stockholm,
I. DUREMAN University
Sweden
and H. SALDE
Hospital
of Uppsala,
Sweden
To most observers the perceived motion of a single object moving in a visual field increases considerably when a second object, moving with the same speed in the opposite direction, is introduced. This will be clearly demonstrated if, for instance, two small bright spots are made to move horizontally to and fro with a pendulum motion on a white screen as indicated in Fig. 1. By making successive comparisons between the velocity of these two dots and that of a single dot in an equal field it will be found that most subjects overestimate the velocity of the two dots up to the double. This increase in perceptual velocity when two moving elements occur in the same field has earlier been investigated by one of the writers (2).
04-----+(-J
Fig. 1
We can very briefly summarize the relevant principles for this phenomenon in the following way: The perceived velocity of two dots in a visual field such as the one mentioned above can appropriately be described as the perceptual equilibrium between divergent influences originating from two different frames of reference. The stationary spatial framework, in relation to which we measure the physical speed of the distal stimulus, forms one of these. The other is constituted by the opposite movement of the second object. The motion of one object is thus seen as relative to the other moving object, ‘and the outcome of this infhtence is a perceptual addition of the physical velocities, a velocity synthesis (3, p. 114). The original study of velocity perception in the relevant constellations was characterized by a rather slight interindividual dispersion of the means obtained by the method already outlined. Some subjects, however, received scores for velocity perception which
290
G. JOHANSSON,
I. DUREMAN
AND
H. SALDE
diverged in a striking manner from those for the rest of the group. Their scores indicated that the static frame of reference was dominant even when the scores of the remaining subjects indicated that the influence of the other moving object was completely predominant. It struck the experimenter as rather remarkable that those subjects (he knew them quite well) who deviated most, experienced distinct difficulties in attaining social contact and also exhibited other pronounced introversive traits. In one case, the personality seemed to be typically schizoid. Thus, these subjects revealed: (a) that they were largely unaffected by the other object in their motion perception (slight velocity synthesis), and (b) that their social contacts were very restricted or that they adopted an attitude of social isolation. It seemed to be possible to hypothesize some kind of functional reselationship between the perceptual and social response observed. Subsequently the writer was able to make certain observations which appeared to confirm this assumption, since two more persons with grave schizoid symptoms showed an extremely low degree of “object dependence” in their motion perception. At this puncture we considered that it was worth while testing the assumption experimentally. As part of an extensive research project for the investigation of the differential validity of certain clinical tests of cognition and personality carried out at the psychiatric clinic of Uppsala, we have tried to test the above mentioned assumption and to give it a more definite formulation. As a starting point for our investigation we formulated the hypothesis in the following way: Those subjects who obtain extremely high scores on the velocity synthesis test (= extremely low degree of velocity synthesis) will in the personality description be characterized by traits such as autism or low degree of social c0ntact.l As a consequence of this hypothesis, the personality traits mentioned were given special attention in the personality analysis of our subjects. APPARATUS
AND
PROCEDURE
Our subjects (Ss.) sit in a chair facing a homogeneous screen (50 x 50 cm) at a distance of 75 cm. Two bright dots about 3 mm in diameter are seen in the central part of this screen. These dots move to and fro along a common* horizontal track in a simple harmonic motion (a pendulum motion, see Fig. 1). Their phase relation is 180”, that is, they turn at the same moment 1. Although these symptoms belong to the more inclusive syndrome of “schizoid personality”, the relative vagueness of the latter concept makes it unsuitable for our purpose.
MOTION
PERCEPTION
AND
PERSONALITY.
I
291
at each end of the common track, cross each other in the middle of the track, turn again at the opposite end, etc. The motions of the dotS have the same frequency, viz. 0.7 cycles per sec. The length of the track is 20 mm, which covers a visual angle of about 1.5 degrees. S has a switch in his left hand. When he presses this switch the two dots disappear, and he now sees a single dot moving along the same horizontal line. This dot has the same frequency as the two first dots, the length of the track, however, is now adjustable. By turning a knob with his right hand S is able to regulate the length of this track and thus also to regulate the velocity of the dot.’ S was instructed to adjust the velocity of the single dot by making a series of comparisons until it appeared equal to that of the two dots. There was no tune restriction whatever. S was allowed to adjust the velocity up or down the scale as he chose, but every adjustment had to begin from one of the termini of the velocity scale. The starting points, which were rotated according to the scheme ABABA, represented velocities which were definitely too high or too low for each S. The scale runs from 50 to 210 units. 200 on the scale means that the velocity of the adjustable dot is equal to that of either of the two standard dots. Thus, this value indicates complete abscence of velocity synthesis (VS). A VS score of 100, on the other hand, indicated complete VS, which is a velocity double that of the standard dots. No instruction about fixation is given: S is allowed to look freely at the moving dots and to follow his spontaneous perception attitude. Ss who observed the change in the length of the motion track in the adjustable field were told not to depend on the length of track as a criterion of equality, but to use only the immediate impression of velocity in the fields. Two groups of subjects were investigated. The first group (N=56) was chosen at random from the male and female patients of the Psychiatric Clinic at the University Hospital of Uppsala. The ages of Ss in this group varied from 20-67 years, the mean age being 37.56 years. The second group (N = 42) was made up of 20 conscripts who were 20 years old and 22 male out-patients from the surgical department of the hospital, who were suffering from minor wounds, fractures, etc. The age of the latter group varied from 18-62 years, and the mean was 36.25 years. All Ss were interviewed and examined by one of the authors who is a senior psychiatrist at the clinic. The latter, of course, had no know2. For description of an apparatus see (2). The stimulus pattern can also be readily produced on the screen of a cathode ray oscillograph with two beams (or an oscillograph + an electronic switch) by means of some rather simple additional devices.
G. JOHANSSON,
292
I. DUREMAN
AND
H. SALDE
ledge of the patients’ VS scores at the time of examination. Short diagnostic summaries were made of the case-reports. These summaries were then sorted into three groups referring to a hypothetic continuum of different “social attitudes”: I. Autistic, withdrawn, reserved, seclusive, retiring. II. Undecided, ambivert. III. Sociable, open, frank, outspoken, expressive. The terms assigned to the three different categories are those used in the descriptive summaries.
RESULTS
The experimental data are given in Table 1, and also in graphic form in Fig. 2. It is evident from Table 1 that there is a marked tendency for Ss characterized as “autistic”, “withdrawn”, “retiring”, “seclusive”, etc., to cluster in the upper part of the VS-scale. This tendency for the “sociable”, t‘frank’, “open”, “expressive” Ss to cluster at the lower end of the VSscale is more accentuated in the normal than in the hospitalized group. As an exploratory test of the statistical significance of these tendencies an analysis of variance was made in accordance with a 3 x 2 factorial design. As can be seen in Table 2, where the complete analysis of the VS-variance is given, a highly significant value of F (P < .OOl) is obtained for the variation between the three different diagnostic groups.
60
70
80
90
100
110
120
130
140
150
160
170
180
190
VS-Score
Fig. 2. Distribution of the three diagnostic categories on the VS-scale. Crosses refer to category I, circles to III. The unfilled space refers to II.
MOTION Table
VS score 60- 64 6% 69 70- 74 75- 79 80- 84 85- 89 go- 94 95- 99 100-104 105-109 110-114 115-119 120-124 125-129 130-134 135-139 140-144 145-149 150-154 155-159 160-164 165-169 170-174 175-179 180-184 N M SD
for
AND the three
PERSONALITY, diagnostic
Undecided Norm. ( Hosp.
I
293
categories.
Sociable Norm. ( Hosp.
Total
-
1
3
-
1
1 1 2 1 1 2
1 2 1 1 2
2. Analysis
Source of variation 1. Between diagnostic categories 2. Between norm. and hosp. 3. Interaction1 x 2 4. Within groups Total
V&scores
Autistic Norm. 1 Hosp.
15 149.0 20.84
Table
I.
PERCEPTION
3 3 5 3 9 6 7 12 9 8 4 6 6 4 1 2 3 2 3 1
2
1 2
4 2 1 4 2 3
1 3 2 2
1 1 2 2 3 3 1
-
2
2
2 1 1 1
-
21 140.3 24.20
9 122.6 7.17
of variance
1
-
-
11 123.4 13.98
of V&scores
Sum of squares
18 110.9 21.93
for
six groups
24 116.6 18.41
of subjects.
1 df 1 Mean square 1
17598
2
1 992 36008
1 1 92
54599
97
8799
1 496 391
98
F 22.504
1.268
(
P
< .OOl
294
G. JOHANSSON,
I. DUREMAN
AND
H. SALDE
In order to complete the analysis of variance, the significance of the difference between the VS-means of the two extreme diagnostic categories was tested. Table 3 shows that the difference between the means of the two extreme diagnostic categories is significant at the . 1% level both in the normal and the hospitalized group. Table 3. t-test of significance of the difference between the VS-means from the two extreme diagnostic categories (autistic - sociable). Group of Ss ( Normal Clinical Total
Diff.
I
t
38.11 23.75 29.80
5.079 3.857 6.169
I
df 31 43 76
I
p < .OOl < .OOl < .OOl
The reliability of the VS-scores
One of the more pertinent methodological problems is concerned with the reliability of the VS-scores. As was mentioned before, the individual VS-score was ascertained as the mean of ten trials. One approach to the question of reliability is to compute the standard error of the mean of the trials for each S. The mean standard error for our normal Ss was 5.63 and for the clinical group 9.11. Thus the clinical Ss were, in general, more indeterminate and less precise in their matching performance than the normal ones. Another approach to the question of reliability was to re-examine our clinical Ss, first after an interval of 6 hours and then a second time after an interval of 24 hours. The control-group was re-examined after an interval of 22 days. The coefficient of stability between the first and second scores was .81, and between the first and third scores .83. For a group of 20 control Ss who were re-examined after an interval of 22 days the coefficient of stability was .79. From these three instances it seems fairly reasonable to conclude that a representative coefficient of stability, for intervals varying from 6 hours to 22 days, for the average of ten trials is .80.
DISCUSSION
1. When conducting our analysis of the intraindividual scatter in connection with the discussion of the reliability of the measurements, we came across a phenomenon which may be of some intrinsic interest. We
MOTION
PERCEPTION
AND
PERSONALITY.
I
295
found that in their matching performance, some of the clinical Ss were greatly influenced by the initial velocity of the adjustable moving dot. It was possible to group their scores for the ten trials in two discrete series; one, originating from adjustments starting from a low velocity, and the other, from adjustments starting from a high velocity. There could be a considerable span between the means of these two groups of scores (m one case, for example, 73-178), while the dispersion within the two groups might remain normal. It is evident, that the mean for the ten trials, as computed in our investigation, must, in such cases, have a value which lies somewhere between the two extremes, and that the dispersion around such means must be very great. We have examined the clinical data for thirteen of the Ss who were the most extreme in this respect. Our impression is, that “a passive, dependent social attitude” may well be taken as a common denominator of the diagnoses. Both the tendency to be influenced by a starting point in a perceptual matching situation (a “lagging” tendency) and the personality traits mentioned above, seem to us to indicate a possible connection with the leveling-sharpening dimension as hypothesized by Klein (1, 4). 2. The VS-scores for the psychiatric patients refer to their pre-treatment period. Some of these patients who later received electroshock or insulin treatment, have been “followed up” by means of successive VS-retesting. Our preliminary impression based on these cases is that neither of these treatments alters, in any conclusive way, the VS-level. 3. The results of our investigation have proved a very good confirmation of the hypothesis which we intended to test. We wish, however, to make it quite clear that the work reported here represents only an introductory, rather exploratory, part of a more comprehensive study of the functional relations between motion perception and personality traits. Consequently, we shall refrain in the present report from explicitly discussing our results as related to theory. We will only state here, that as a starting point for the forthcoming work, we have tentatively hypothesized the existence of an analytical, isolating or self-oriented perceptual attitude behind the extremely high VS-scores. We also assume that this attitude is a formal pattern which we may expect to find in other suitable perceptual situations as well as in some forms of intellectual, emotional and social behaviour. The first part of this set of assumptions has a rather stable basis. We know that the basic relations between a stimulus situation built up of several elements in simple harmonic motion and different forms
296
G. JOHANSSON,
I. DUREMAN
AND
H. SALDE
of perceptual responses to this stimulation are all consistent from a mathematical point of view, and can be described from the standpoint of psychophysics. The response type may vary, e. g., with a change in fixation attitude, but in any case it is a mathematically correct representation of the stimulation (3). The two additional assumptions are merely reformulations of the common general assumption on which all sound theorizing about perception-personality relations is based. Thus, we definitely base our work on a psychophysical relationship between stimulation and perception, and not on a subjectivity of perception which is all too often presumed to exist in this field. SUMMARY Experiments in the field of motion perception had indicated that there were good reasons for assuming a correlation between an analytical or isolating attitude in perception and a tendency to social isolation. The hypothesis advanced was: Those Ss who obtain extremely high scores in the velocity synthesis test, will be characterized, in the description of their personality, by traits like autism, or a low degree of social contact. This hypothesis has been tested and the result may be taken as confirming the validity of the hypothesis. REFERENCES 1. Holtzmann, P. S. and Klein, G. S., Cognitive system-principles of leveling and sharpening. J. Psychol., 1954, 37, 105-122. 2. Johansson, G., Configurations in the perception of velocity. Acta Psychol., 1950, 7, 25-79. 3. Johansson, G., Configurations in event perception. Uppsala: Almquist & Wiksell, 1950. 4.
Klein, G. S., The personal world through perception. In Blake, R. R., and Ramsay, G. V., eds., Perception: An approach to personality. New York: Ronald Press, 1951.
PERCEPTION
AND
PERSONALITY.4
G. JOHANSSON, University
of Stockholm,
I. DUREMAN University
Sweden
and H. SALDE
Hospital
of Uppsala,
Sweden
To most observers the perceived motion of a single object moving in a visual field increases considerably when a second object, moving with the same speed in the opposite direction, is introduced. This will be clearly demonstrated if, for instance, two small bright spots are made to move horizontally to and fro with a pendulum motion on a white screen as indicated in Fig. 1. By making successive comparisons between the velocity of these two dots and that of a single dot in an equal field it will be found that most subjects overestimate the velocity of the two dots up to the double. This increase in perceptual velocity when two moving elements occur in the same field has earlier been investigated by one of the writers (2).
04-----+(-J
Fig. 1
We can very briefly summarize the relevant principles for this phenomenon in the following way: The perceived velocity of two dots in a visual field such as the one mentioned above can appropriately be described as the perceptual equilibrium between divergent influences originating from two different frames of reference. The stationary spatial framework, in relation to which we measure the physical speed of the distal stimulus, forms one of these. The other is constituted by the opposite movement of the second object. The motion of one object is thus seen as relative to the other moving object, ‘and the outcome of this infhtence is a perceptual addition of the physical velocities, a velocity synthesis (3, p. 114). The original study of velocity perception in the relevant constellations was characterized by a rather slight interindividual dispersion of the means obtained by the method already outlined. Some subjects, however, received scores for velocity perception which
290
G. JOHANSSON,
I. DUREMAN
AND
H. SALDE
diverged in a striking manner from those for the rest of the group. Their scores indicated that the static frame of reference was dominant even when the scores of the remaining subjects indicated that the influence of the other moving object was completely predominant. It struck the experimenter as rather remarkable that those subjects (he knew them quite well) who deviated most, experienced distinct difficulties in attaining social contact and also exhibited other pronounced introversive traits. In one case, the personality seemed to be typically schizoid. Thus, these subjects revealed: (a) that they were largely unaffected by the other object in their motion perception (slight velocity synthesis), and (b) that their social contacts were very restricted or that they adopted an attitude of social isolation. It seemed to be possible to hypothesize some kind of functional reselationship between the perceptual and social response observed. Subsequently the writer was able to make certain observations which appeared to confirm this assumption, since two more persons with grave schizoid symptoms showed an extremely low degree of “object dependence” in their motion perception. At this puncture we considered that it was worth while testing the assumption experimentally. As part of an extensive research project for the investigation of the differential validity of certain clinical tests of cognition and personality carried out at the psychiatric clinic of Uppsala, we have tried to test the above mentioned assumption and to give it a more definite formulation. As a starting point for our investigation we formulated the hypothesis in the following way: Those subjects who obtain extremely high scores on the velocity synthesis test (= extremely low degree of velocity synthesis) will in the personality description be characterized by traits such as autism or low degree of social c0ntact.l As a consequence of this hypothesis, the personality traits mentioned were given special attention in the personality analysis of our subjects. APPARATUS
AND
PROCEDURE
Our subjects (Ss.) sit in a chair facing a homogeneous screen (50 x 50 cm) at a distance of 75 cm. Two bright dots about 3 mm in diameter are seen in the central part of this screen. These dots move to and fro along a common* horizontal track in a simple harmonic motion (a pendulum motion, see Fig. 1). Their phase relation is 180”, that is, they turn at the same moment 1. Although these symptoms belong to the more inclusive syndrome of “schizoid personality”, the relative vagueness of the latter concept makes it unsuitable for our purpose.
MOTION
PERCEPTION
AND
PERSONALITY.
I
291
at each end of the common track, cross each other in the middle of the track, turn again at the opposite end, etc. The motions of the dotS have the same frequency, viz. 0.7 cycles per sec. The length of the track is 20 mm, which covers a visual angle of about 1.5 degrees. S has a switch in his left hand. When he presses this switch the two dots disappear, and he now sees a single dot moving along the same horizontal line. This dot has the same frequency as the two first dots, the length of the track, however, is now adjustable. By turning a knob with his right hand S is able to regulate the length of this track and thus also to regulate the velocity of the dot.’ S was instructed to adjust the velocity of the single dot by making a series of comparisons until it appeared equal to that of the two dots. There was no tune restriction whatever. S was allowed to adjust the velocity up or down the scale as he chose, but every adjustment had to begin from one of the termini of the velocity scale. The starting points, which were rotated according to the scheme ABABA, represented velocities which were definitely too high or too low for each S. The scale runs from 50 to 210 units. 200 on the scale means that the velocity of the adjustable dot is equal to that of either of the two standard dots. Thus, this value indicates complete abscence of velocity synthesis (VS). A VS score of 100, on the other hand, indicated complete VS, which is a velocity double that of the standard dots. No instruction about fixation is given: S is allowed to look freely at the moving dots and to follow his spontaneous perception attitude. Ss who observed the change in the length of the motion track in the adjustable field were told not to depend on the length of track as a criterion of equality, but to use only the immediate impression of velocity in the fields. Two groups of subjects were investigated. The first group (N=56) was chosen at random from the male and female patients of the Psychiatric Clinic at the University Hospital of Uppsala. The ages of Ss in this group varied from 20-67 years, the mean age being 37.56 years. The second group (N = 42) was made up of 20 conscripts who were 20 years old and 22 male out-patients from the surgical department of the hospital, who were suffering from minor wounds, fractures, etc. The age of the latter group varied from 18-62 years, and the mean was 36.25 years. All Ss were interviewed and examined by one of the authors who is a senior psychiatrist at the clinic. The latter, of course, had no know2. For description of an apparatus see (2). The stimulus pattern can also be readily produced on the screen of a cathode ray oscillograph with two beams (or an oscillograph + an electronic switch) by means of some rather simple additional devices.
G. JOHANSSON,
292
I. DUREMAN
AND
H. SALDE
ledge of the patients’ VS scores at the time of examination. Short diagnostic summaries were made of the case-reports. These summaries were then sorted into three groups referring to a hypothetic continuum of different “social attitudes”: I. Autistic, withdrawn, reserved, seclusive, retiring. II. Undecided, ambivert. III. Sociable, open, frank, outspoken, expressive. The terms assigned to the three different categories are those used in the descriptive summaries.
RESULTS
The experimental data are given in Table 1, and also in graphic form in Fig. 2. It is evident from Table 1 that there is a marked tendency for Ss characterized as “autistic”, “withdrawn”, “retiring”, “seclusive”, etc., to cluster in the upper part of the VS-scale. This tendency for the “sociable”, t‘frank’, “open”, “expressive” Ss to cluster at the lower end of the VSscale is more accentuated in the normal than in the hospitalized group. As an exploratory test of the statistical significance of these tendencies an analysis of variance was made in accordance with a 3 x 2 factorial design. As can be seen in Table 2, where the complete analysis of the VS-variance is given, a highly significant value of F (P < .OOl) is obtained for the variation between the three different diagnostic groups.
60
70
80
90
100
110
120
130
140
150
160
170
180
190
VS-Score
Fig. 2. Distribution of the three diagnostic categories on the VS-scale. Crosses refer to category I, circles to III. The unfilled space refers to II.
MOTION Table
VS score 60- 64 6% 69 70- 74 75- 79 80- 84 85- 89 go- 94 95- 99 100-104 105-109 110-114 115-119 120-124 125-129 130-134 135-139 140-144 145-149 150-154 155-159 160-164 165-169 170-174 175-179 180-184 N M SD
for
AND the three
PERSONALITY, diagnostic
Undecided Norm. ( Hosp.
I
293
categories.
Sociable Norm. ( Hosp.
Total
-
1
3
-
1
1 1 2 1 1 2
1 2 1 1 2
2. Analysis
Source of variation 1. Between diagnostic categories 2. Between norm. and hosp. 3. Interaction1 x 2 4. Within groups Total
V&scores
Autistic Norm. 1 Hosp.
15 149.0 20.84
Table
I.
PERCEPTION
3 3 5 3 9 6 7 12 9 8 4 6 6 4 1 2 3 2 3 1
2
1 2
4 2 1 4 2 3
1 3 2 2
1 1 2 2 3 3 1
-
2
2
2 1 1 1
-
21 140.3 24.20
9 122.6 7.17
of variance
1
-
-
11 123.4 13.98
of V&scores
Sum of squares
18 110.9 21.93
for
six groups
24 116.6 18.41
of subjects.
1 df 1 Mean square 1
17598
2
1 992 36008
1 1 92
54599
97
8799
1 496 391
98
F 22.504
1.268
(
P
< .OOl
294
G. JOHANSSON,
I. DUREMAN
AND
H. SALDE
In order to complete the analysis of variance, the significance of the difference between the VS-means of the two extreme diagnostic categories was tested. Table 3 shows that the difference between the means of the two extreme diagnostic categories is significant at the . 1% level both in the normal and the hospitalized group. Table 3. t-test of significance of the difference between the VS-means from the two extreme diagnostic categories (autistic - sociable). Group of Ss ( Normal Clinical Total
Diff.
I
t
38.11 23.75 29.80
5.079 3.857 6.169
I
df 31 43 76
I
p < .OOl < .OOl < .OOl
The reliability of the VS-scores
One of the more pertinent methodological problems is concerned with the reliability of the VS-scores. As was mentioned before, the individual VS-score was ascertained as the mean of ten trials. One approach to the question of reliability is to compute the standard error of the mean of the trials for each S. The mean standard error for our normal Ss was 5.63 and for the clinical group 9.11. Thus the clinical Ss were, in general, more indeterminate and less precise in their matching performance than the normal ones. Another approach to the question of reliability was to re-examine our clinical Ss, first after an interval of 6 hours and then a second time after an interval of 24 hours. The control-group was re-examined after an interval of 22 days. The coefficient of stability between the first and second scores was .81, and between the first and third scores .83. For a group of 20 control Ss who were re-examined after an interval of 22 days the coefficient of stability was .79. From these three instances it seems fairly reasonable to conclude that a representative coefficient of stability, for intervals varying from 6 hours to 22 days, for the average of ten trials is .80.
DISCUSSION
1. When conducting our analysis of the intraindividual scatter in connection with the discussion of the reliability of the measurements, we came across a phenomenon which may be of some intrinsic interest. We
MOTION
PERCEPTION
AND
PERSONALITY.
I
295
found that in their matching performance, some of the clinical Ss were greatly influenced by the initial velocity of the adjustable moving dot. It was possible to group their scores for the ten trials in two discrete series; one, originating from adjustments starting from a low velocity, and the other, from adjustments starting from a high velocity. There could be a considerable span between the means of these two groups of scores (m one case, for example, 73-178), while the dispersion within the two groups might remain normal. It is evident, that the mean for the ten trials, as computed in our investigation, must, in such cases, have a value which lies somewhere between the two extremes, and that the dispersion around such means must be very great. We have examined the clinical data for thirteen of the Ss who were the most extreme in this respect. Our impression is, that “a passive, dependent social attitude” may well be taken as a common denominator of the diagnoses. Both the tendency to be influenced by a starting point in a perceptual matching situation (a “lagging” tendency) and the personality traits mentioned above, seem to us to indicate a possible connection with the leveling-sharpening dimension as hypothesized by Klein (1, 4). 2. The VS-scores for the psychiatric patients refer to their pre-treatment period. Some of these patients who later received electroshock or insulin treatment, have been “followed up” by means of successive VS-retesting. Our preliminary impression based on these cases is that neither of these treatments alters, in any conclusive way, the VS-level. 3. The results of our investigation have proved a very good confirmation of the hypothesis which we intended to test. We wish, however, to make it quite clear that the work reported here represents only an introductory, rather exploratory, part of a more comprehensive study of the functional relations between motion perception and personality traits. Consequently, we shall refrain in the present report from explicitly discussing our results as related to theory. We will only state here, that as a starting point for the forthcoming work, we have tentatively hypothesized the existence of an analytical, isolating or self-oriented perceptual attitude behind the extremely high VS-scores. We also assume that this attitude is a formal pattern which we may expect to find in other suitable perceptual situations as well as in some forms of intellectual, emotional and social behaviour. The first part of this set of assumptions has a rather stable basis. We know that the basic relations between a stimulus situation built up of several elements in simple harmonic motion and different forms
296
G. JOHANSSON,
I. DUREMAN
AND
H. SALDE
of perceptual responses to this stimulation are all consistent from a mathematical point of view, and can be described from the standpoint of psychophysics. The response type may vary, e. g., with a change in fixation attitude, but in any case it is a mathematically correct representation of the stimulation (3). The two additional assumptions are merely reformulations of the common general assumption on which all sound theorizing about perception-personality relations is based. Thus, we definitely base our work on a psychophysical relationship between stimulation and perception, and not on a subjectivity of perception which is all too often presumed to exist in this field. SUMMARY Experiments in the field of motion perception had indicated that there were good reasons for assuming a correlation between an analytical or isolating attitude in perception and a tendency to social isolation. The hypothesis advanced was: Those Ss who obtain extremely high scores in the velocity synthesis test, will be characterized, in the description of their personality, by traits like autism, or a low degree of social contact. This hypothesis has been tested and the result may be taken as confirming the validity of the hypothesis. REFERENCES 1. Holtzmann, P. S. and Klein, G. S., Cognitive system-principles of leveling and sharpening. J. Psychol., 1954, 37, 105-122. 2. Johansson, G., Configurations in the perception of velocity. Acta Psychol., 1950, 7, 25-79. 3. Johansson, G., Configurations in event perception. Uppsala: Almquist & Wiksell, 1950. 4.
Klein, G. S., The personal world through perception. In Blake, R. R., and Ramsay, G. V., eds., Perception: An approach to personality. New York: Ronald Press, 1951.