Harvard Psychological Studies Part 35

F. 2.40 "

C. 4.80 "

B. 4.98 "

I. 6.06 "

G. 11.15 "

H. 11.84 "

A. 16.05 "

K. 16.70 "

D. 25.80 "

Arranging them by the average absence of the suppressed image we have this order:

B. 251.08 sec D. 193.89 "

H. 81.02 "

C. 62.07 "

I. 59.72 "

K. 31.83 "

J. 31.75 "

G. 19.47 "

A. 10.44 "

F. 10.09 "

It is to be remarked, however, that the ability to keep the suppressed image out of the field increased with practice and that A. and F. had less than half the number of experiments that the rest had. D., who had but two thirds as many as most of the other subjects and therefore had less practice in suppressing the image, stands yet second in respect to this ability.

If we compare the subjects with regard to _first_ efforts and _first_ absences only, we obtain the following orders:

According to Ave. Time req. According to Ave. Absence for first Suppression. of Image after first Suppression.

J. 3.59 sec. B. 270.44 sec.

B. 5.79 " D. 190.07 "

C. 7.88 " F. 86.07 "

I. 9.77 " H. 73.27 "

F. 12.67 " K. 71.90 "

H. 15.27 " I. 53.83 "

K. 21.63 " C. 43.08 "

G. 21.88 " J. 32.18 "

D. 23.28 " G. 20.39 "

A. 28.32 " A. 11.29 "

Arranging the groups of images suppressed according to the average times of all suppressions and absences we have these orders:

Suppression. Absences.

Central Images, 5.41 Marginal Images, 125.12 Upper " 6.95 Sundry " 68.78 Left " 8.60 Left " 51.26 Right " 8.94 Lower " 50.04 Lower " 9.11 Right " 43.93 Marginal " 11.35 Upper " 32.35 Sundry " 12.09 Central " 26.54

SUBJECTIVE.

Most of the subjects imaginatively placed the image to be suppressed behind the screen, in a drawer, in their closed hands, pushed it forward into the remote distance, sliced up, burned up, or pulverized and so destroyed it. B. and D. 'thought it away' directly, without mechanism or device, or got rid of it 'by a pure act of will.'

Superposition was tried, frequently with success, but at times the under image shone through. When the objects were colored discs one superposed on the other, the subject spread over the whole surface the color of the image to be retained, but at times this resulted in there being two shades of the upper color, and a yellow above a red changed to an orange. When red was above yellow, the red appeared more highly illuminated. a.s.sociations with objects of the color of the retained image were found helpful but tended to modify the original color. Such a.s.sociations also, at times, by secondary a.s.sociations brought back the suppressed image. For example, when thinking of b.u.t.tercups to enforce a yellow image, the picture of gra.s.s surrounding the flowers brought back the suppressed green image. Concentration of the attention on the image to be retained and an ignoring of the other was, on the whole, the method usually and successfully followed. This concentration was helped by imagining the image marked off into minute squares which were carefully counted. Numerous other devices of a similar character were used. Objects having many details and those lending themselves readily to suggestions of action (as a china animal) were the most helpful in enabling the subject to concentrate his attention on their image to the exclusion of another. Some subjects conceived themselves as tracing with a pencil the outline and details of the retained image. Frequently, when the two images were originally near each other and one alone was being held by close scrutiny of its parts, when this scrutiny reached the part of the image which was nearest the position of the suppressed image, the suppressed image returned. The original a.s.sociation between the two images was often broken up by change of the position or shape of the one to be suppressed. But devices soon became 'worn out' and new ones had to be resorted to.

Motor impulses played a large part in the process of suppression, such as head and eye movement away from the image to be suppressed, contraction of the muscles of the forehead and scalp, occasional 'setting' of the teeth, pressure together of the hands when they were supposed to be holding the image and of the knees under like circ.u.mstances. The eye traced outline and details and the more actively it could be so employed the more successful was the suppression. The sensations of accommodation and of focusing previously referred to were repeated in this series. Enunciation also was very common.

Frequent comparison of the image with the percept was made at the close of experiments and showed the utmost diversity in size, vividness and distinctness. During an experiment when the suppressed image came back, it was rarely more than a mere blur of color; in two or three instances the form came without color. Green was found to be a difficult color to hold. C. had an orange after-image from a retained yellow image, a red image having been suppressed. Between the images of a gray disc and an orange disc, three inches apart, he had a blue disc. J., while suppressing an orange disc and retaining a green disc, noticed that 'when off the fovea the whole green disc became bright orange.' There was always a sense of readiness on the part of the suppressed image to slip back. As C. expressed this, "The thing suppressed exists in the fringe of consciousness." The recurring image usually came back at its original position even when the retained image was being held in a different part of the field. In such cases the retained image at once resumed its original place.

G. and J. were successful in proportion as they freed themselves from the nervous strain of anxiety as to the result.

V. MOVEMENTS OF A SINGLE IMAGE, THE OBJECT HAVING BEEN MOVED DURING THE EXPOSURE.

In an additional series of experiments with five of the same subjects (B., G., H., I. and K.), the object was moved during the five seconds of exposure either right, left, up or down, a distance of about six to eight inches, and back again. In this way the subject was supplied with further material of a pure memory type and it was believed that some addition to our knowledge of the nature of the control of the image might thus be made by securing data contrasting the construction and the more purely reminiscent work of the imagination.

The question proposed is as follows: Does the fact that a certain movement of an object was presented to the optical perception give an advantage in time, or ease, to the mental recall of that object as so moving, over its recall as moving in other directions? The subjective experiences during such recalls may be expected to throw light upon the matter.

The subject, with closed eyes, was requested to move the mental image of the object in the four directions indicated above, returning it after each movement to its original position, and the time of each movement was recorded and, as well, the report of the subject with regard to his subjective experiences. There were sixteen hundred movements in all, eight hundred away from the original position of the image (two hundred in each of the four directions mentioned above) and eight hundred in returning to the original position.

Besides these experiments, other movements of the object during exposure were made, such as inversion, rotation, change from the vertical to the horizontal position and vice versa, rolling, oblique movements and the subjective phenomena were recorded when the subject had repeated with the image the designated movements. In all the experiments the objects were moved by the hand of the conductor of the experiment.

Table VII. gives the time record in seconds of these experiments for each subject under each of the four variations: Movement of the object to right, left, up, down.

TABLE VII.

MOVEMENTS OF A SINGLE IMAGE, THE OBJECT HAVING BEEN MOVED DURING THE TIME OF OPTICAL STIMULATION. AVERAGE TIME IN SECONDS. TEN MOVEMENTS IN EACH DIRECTION FOR EACH SUBJECT.

_a_. Object moved to right.

Subject R. Return L. Return Up Return Down Return Aver.

B. 0.57 0.75 0.62 0.60 0.64 0.35 0.42 0.37 0.62 0.44 G. 0.55 0.60 0.55 0.57 0.57 0.27 0.25 0.27 0.25 0.26 H. 6.95 6.90 6.47 6.40 6.65 5.40 5.55 4.50 5.00 5.11 I. 2.05 2.10 2.05 2.22 2.10 1.15 1.35 1.32 1.57 1.35 K. 2.35 2.97 2.42 2.62 2.59 1.17 1.20 1.17 1.55 1.28 Ave. 2.49 2.66 2.02 2.48 2.52 1.67 1.75 1.53 1.80 1.69

Ave. to right, 2.49 Ave. of other movements, 2.52 Grand average, 2.10

_b_. Object moved to left.

B. 0.72 0.60 0.62 0.60 0.64 0.52 0.40 0.52 0.42 0.47 G. 0.67 0.45 0.55 0.67 0.59 0.42 0.35 0.35 0.37 0.37 H. 8.22 5.95 6.52 6.42 6.78 5.82 4.10 4.37 5.55 4.96 I. 2.40 1.30 2.25 2.72 2.17 1.97 1.22 0.95 1.47 1.40 K. 2.45 2.57 2.25 2.00 2.30 1.70 1.60 1.32 1.35 1.49 Ave. 2.89 2.17 2.44 2.48 2.50 2.09 1.53 1.50 1.83 1.74

Ave. to left, 2.17 Ave. of other movements, 2.60 Grand average, 2.12

_c_. Object moved up.

B. 0.75 0.62 0.42 0.57 0.59 0.32 0.50 0.42 0.37 0.40 G. 0.65 0.57 0.45 0.47 0.54 0.35 0.27 0.25 0.27 0.29 H. 6.77 6.25 6.85 6.15 6.57 5.27 5.55 5.30 5.30 5.35 I. 2.47 2.27 1.85 2.65 2.31 1.25 1.00 0.87 1.10 1.05 K. 3.40 2.72 1.42 2.20 2.44 1.50 1.37 1.27 1.17 1.33 Ave. 2.81 2.49 2.20 2.41 2.48 1.74 1.74 1.62 1.70 1.69

Ave. up, 2.20 Ave. of other movements, 2.57 Grand average, 2.08

_d_. Object moved down.

B. 0.80 0.72 0.70 0.57 0.70 0.42 0.42 0.50 0.42 0.44 G. 0.60 0.60 0.55 0.47 0.55 0.25 0.25 0.27 0.27 0.26 H. 6.77 6.80 6.80 8.77 7.29 5.90 6.35 4.55 5.55 5.59 I. 2.30 2.20 2.22 1.80 2.13 1.30 1.20 1.15 1.42 1.27 K. 3.15 2.75 2.95 2.30 2.79 1.62 1.57 1.12 1.25 1.39 Ave. 2.72 2.61 2.64 2.78 2.69 1.90 1.92 1.52 1.78 1.79

Ave. down, 2.78 Ave. of other movements, 2.66 Grand average, 2.24

NUMERICAL.

As each movement may be compared with three other movements, and as there were five subjects and four variations in the conditions, there are sixty opportunities of comparing the time required to move the image in the direction in which the object was moved with the time taken to move it in the other directions. In 45 instances the time was less, in 3 the same, and in 12 greater.