Harvard Psychological Studies Part 31

To To Subjects Right Return Left Return Up Return Down Return Averages B. 1.30 1.07 1.06 1.11 1.13 0.58 0.73 0.46 0.45 0.55

G. 1.44 1.15 0.99 0.82 1.10 0.92 0.89 0.76 0.57 0.78

H. 7.12 6.42 5.96 5.85 6.34 4.51 4.41 4.36 4.40 4.42

I. 1.28 1.34 1.62 1.47 1.43 0.67 0.62 0.86 0.72 0.72

J. 1.71 1.42 1.40 1.14 1.50 1.34 1.53 0.77 0.74 1.09

K. 4.81 4.64 3.29 3.28 4.01 2.40 2.71 1.91 1.56 2.14

Averages 2.95 2.67 2.39 2.23 2.59 1.72 1.82 1.52 1.41 1.62

NUMERICAL.

The general averages for the different movements show that movement to the right was hardest, to the left next; while movement downward was the easiest. A marked exception is seen in I., for whom the upward movement was the hardest and movement to the right was the easiest. J.

found movement to the left hardest. For the return movements, the general averages show that the return from the left is the hardest, from the right next; while from below is the easiest. Here again I.

found the return from above the hardest and from below the next hardest; while from the left was the easiest.

Arranging the subjects in the order of the average time, taken for all the movements, including the returns to the original position, we have

H. 5.35 average time out and back.

K. 3.07 " " " " "

J. 1.29 " " " " "

I. 1.07 " " " " "

G. .94 " " " " "

B. .84 " " " " "

SUBJECTIVE.

All the six subjects whose time records appear in Table I. and also four others whose time was not recorded reported eye movements, or a tendency to eye movement. A. and K. reported that when the image was dim there was accommodation as for long vision and when the image was vivid there was accommodation as for near vision. B. ideated the new position and the eye movement occurred automatically. G. reported a contraction of the scalp muscles and a tendency to cast the eyes up and locate the image at the back of the head inside; this was an inveterate habit. He reported also accommodation for the different distances of the image and an after-feeling of strain in the head. H.

reported a strong tendency in the eyes to return to the center, _i.e._, the original position, and to carry the image back there. All the subjects frequently reported a sense of relief in the eye muscles when the command to return the image to the center was given--also, a tension in the forehead in the upward movement which was accentuated (with H.) when there was headache. J. reported, 'always eye strain,'

and noticed that the eyes usually turned as far as the new position, but sometimes stopped short of it. K. reported first an eye movement, then an ideation of the image in the new position. E. and H. turned the head to right and left for movements of the image in those directions. A., B., E. and F. believed that they could inhibit the eye movement. Subjects were at times unconscious of eye movements. H.

articulated the names of the colors of the image and found that it aided the movement of the image to say to himself, for example: "Don't you see that blue square there?"

All but J. reported a loss in vividness and also, though to a less degree, in distinctness whenever the image was moved away from the center. J. found no difference. H. reported that details of the object which were reproduced in the image when at the center were not discernible in the image in other positions, also that at the left the image was more vivid than at the right. B.'s memory image of a watch, three minutes after it was called up, was still so clear that he read from it the time. E., who was an experienced photographer, had no difficulty in recalling outline, light and shade, but had difficulty in reproducing color. I. frequently lost the form in making the required improvements.

Under manipulation the memory image usually retained its distinctness and vividness with no loss or with but slight loss when in its original position, to the end of the five minutes of the experiment.

The image, also, seldom disappeared except for the momentary disappearances in pa.s.sing from one position to another, which are referred to later. Under pa.s.sive observation of the memory image disappearances, though of short duration, were frequent and there was a noticeable fading away of color and loss of outline.

The memory image almost without exception, when first recalled, was located in the direction and at the distance of the object presented.

In moving from the center to right and left the image remained in the same plane with a few exceptions; in moving up and down it moved on an arc whose center was at the eye. This was especially true of the downward motion, which was almost always to a greater distance than any of the other motions.

C., D., F. and H. felt the need of a support for the image in any except the central position. This was true especially of the position above the center, but was entirely overcome by practice by C., F. and H., and partially by D. In movements where time was to be recorded, the distance was from six to eighteen inches, but the image could be carried by all the eleven subjects to any part of the room or beyond the room. Usually the method followed was to fix the attention on the suggested position and then the image appeared there, sometimes complete at the outset, but usually in part at first, then developing instantly to completion. When the subject was requested to trace the image _in transitu_, this could usually be accomplished, but the time was much longer. Frequently, in such a case, the image was lost during the last third or fifth of its journey. J. "felt conscious of a something that went in the suggested direction but did not develop details out of this material; had to await development of the image at the new locality." "At times _forced_ this development out of the vague something that seemed to go over." G. had 'no feeling of transition in s.p.a.ce.' K. did not perceive the image _in transitu_. I.

perceived the image _in transitu_ when the movement was away from the center but when the image was to return to the center its pa.s.sage was too quick to be followed; 'it came out at the center.'

J. noticed that in moving from the center the image took a curved path towards himself, and that the position _to_ which the image moved always seemed further away than the position _from_ which it came, but the new position seemed to be readjusted when the next movement occurred.

The return to the center seemed easier to all the subjects except G., who was conscious of no difference between the movements with respect to ease. Several described the return to the center as like the return of a small ball snapped back by a stretched elastic cord.

With D. a suggestion of weight in the perception of the object was a hindrance to moving its memory image. Also the image of a short piece of bra.s.s tubing persisted in rolling off the table and along the floor and could not be held stationary. Other objects rotated rapidly, and much effort was needed to 'slow down' the rotation and to bring the objects to rest and keep them at rest.

II. CHANGES OF COLOR OF A SINGLE IMAGE.

Tables II. and III. show the results of experiments in changing the color of a single image. This was usually a square, sometimes a disc.

The time of optical perception was five seconds. After the disappearance of after-images, if there were any, eighteen to twenty-four changes were made in the color of the memory image, occupying from four and a half to six minutes.

The colors were saturated blue, green, yellow and red, and each one was changed into each of the other colors and then restored. The order of change was varied to avoid uniformity of succession. The four colors were shown to the subjects each day before the experiments began, to establish a standard. The time was taken with a stop-watch, and includes the time between the director's word of command, 'green,'

etc., and the subject's report, 'now,' or 'green,' etc. It includes, therefore, two reaction times. The subject reported 'now' the instant he secured the desired color, not waiting for the completion of the shape that usually followed.

TABLE II.

CHANGES OF COLOR. SINGLE IMAGE. 72 CHANGES OF EACH COLOR.

[Label 1: Subject.]

[Label 2: To Green.]

[Label 3: Return to Blue.]

[Label 4: To Yellow.]

[Label 5: Return to Blue.]

[Label 6: To Red.]

[Label 7: Return to Blue.]

[Label 8: To Blue.]

[Label 9: Return to Green.]

[Label 10: To Yellow.]

[Label 11: Return to Green.]

[Label 12: To Red]

[Label 13: Return to Green.]

From Blue. From Green.

[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]

B. 1.72 0.50 1.66 0.38 1.81 0.50 1.23 0.56 1.10 0.65 1.33 0.56 G. 1.15 0.60 1.10 0.79 0.89 0.65 1.75 0.87 1.04 0.75 1.35 0.71 H. 4.67 4.25 4.87 4.06 4.81 3.83 5.27 4.50 5.81 4.89 5.37 4.94 I. 2.27 1.25 1.77 1.19 1.83 1.25 2.15 0.93 1.71 1.04 1.92 1.15 J. 1.38 0.81 1.29 0.94 1.29 0.95 1.65 1.08 1.15 0.77 1.60 0.81 K. 2.35 1.71 1.96 1.66 2.10 1.19 2.25 1.25 2.17 1.73 2.44 1.27

Av. 2.26 1.52 2.11 1.50 2.15 1.39 2.41 1.53 2.15 1.65 2.34 1.57

[Label 1: Subject.]

[Label 2: To Blue.]

[Label 3: Return to Yellow.]

[Label 4: To Green.]

[Label 5: Return to Yellow.]

[Label 6: To Red.]

[Label 7: Return to Yellow.]

[Label 8: To Blue.]