SUBJECTIVE.

For seven of the subjects, mental repet.i.tion of the name of the color (usually accompanied by articulatory movements) tended to bring up the color, and one other subject occasionally used this method of bringing about a change that was difficult. With D. the color did not come at repet.i.tion of the name. G. was a.s.sisted by auditory recall of the name. Nine subjects reported a feeling of strain, usually in the eyes as of focusing, occurring especially when there seemed a difficulty in producing the desired change. The tension attended almost exclusively changes of the presented color, not restorations of that color. For D.

this strain was considerable, for G. there was also an after-feeling of strain in the head. For G. the image was clearest when the feeling of strain was least, and J. secured the promptest and clearest results when he could most nearly rid himself of anxiety as to the result. K.

in one instance (a change from green to yellow) became conscious of the setting of his jaws and motions of feet and body in aid of his attempt. H. frequently had the feeling of physical fatigue.

In most cases the restoration of the presented color was as a complete square, triangle, etc. In changes from the presented color the new color appeared at a corner, or edge, or as a patch at the center. With E. the "color flashed over the whole field and then had to be restricted to the figure." B. "held the outline, emptied of the old color, while it was filled in with the new." D. "had a clear outline, and the new color came in small blotches inside, and effort spread them out to cover the whole figure." For I. the "new color came sliding in from the right side over the old, which, however, disappeared as if it were moving out of focus." With A. the new color usually came from either the lower left-hand or the upper right-hand corner. F. kept a clear outline and the new color came in from the right.

When E. found it difficult to create at the center the desired color, he thought of some object (garment, gra.s.s, sky, etc.) of that color and then transferred it to fill in the outline preserved at the center. B. moved the colored figure aside and in its place put one of the desired color, moved the new figure up to the old and there superposed it. With G. the new colors seemed of new material and there was felt to be an acc.u.mulation about the center, of old color-material. Then he located the square outside of this imaginary debris and began again. H. found that the colors of his own experiments, in which he used color squares framed in black, came to his mind at the names of the desired colors, and the a.s.sociation soon gave him the figure also. I. located the new colors around the presented one, first all at the right; then green at the left, red at the right, yellow above, when presented blue was at the center; then yellow and green were at the upper left-hand corner, while red came from behind. The new color 'slid in over the old.' It was found easier to secure the desired color when its position was known beforehand. J.

also used a similar device. He 'turned towards the places and brought out the required color and filled the central outline with it.' He tried to break up this scheme and got red without going after it but found himself 'at a loss to find the colors.' Later he succeeded so that the required color simply appeared in the outline of the old color at the center. K. turned his eyes to corners of the central outline, then to the center, and found that this aided in developing the desired color from the corners inward. When difficulty arose, he experienced muscular tension in body and legs and jaws.

Five of the subjects considered the change from a presented color to blue the hardest and one found the change to red hardest. Green was placed second in difficulty by one, and blue second by the one who found red the hardest. Three reported the change to yellow the easiest and two the change to red.

The change from red to yellow caused 'an unpleasant sensation' in C.

and the new figure 'had a maroon halo.'

A. in returning from green or blue to yellow pa.s.sed through a gray; so, once, in changing from yellow to green, and once, green to red.

With A. blue retinal clouds, which often came, aided changes to blue and hindered at times changes to other colors. B. had a fusion of yellow and red in changing from yellow to red. G. had a tendency to leave uncolored the lower left-hand corner and it 'was wood-colored'; G. had a gray image as the result of fusion of retinal clouds with red memory image. With H. blue always came in as robin's-egg blue, which then had to be changed to the standard blue. In one instant the green memory image seemed to shift into a purple and change to a positive retinal image which interfered with changes to other colors. J. found whistling and humming an aid in relaxing an unnatural state of tension which would hinder the best results. To increase the vividness of the image he would recall the black background on which the colored squares had hung. In one experiment K. became 'desperately tired of yellow,' which was the presented color, so that his 'mind was ready to jump to any color rather than yellow.' The returns to yellow were, in this experiment, slower than the changes from yellow.

The images sometimes changed sizes, being at times smaller, but usually larger than the object. In one experiment of C. the image was four times the size of the object, which was a green square with sides of one inch.

III. MOVEMENTS OF TWO IMAGES IN THE SAME AND IN DIFFERENT DIRECTIONS.

Table IV. gives the results of experiments in the movements of two images, the objects presented being colored squares or discs. Time of perception was five seconds. After the disappearance of after-images, if there were any, eighteen to twenty-four movements with returns to original positions were made, occupying five or six minutes. The colors were saturated blue, green, yellow and red. Four of the movements were such as separated the two images, and in four the two moved uniformly. The first four movements were right and left, left and right, up and down, down and up; the left-hand object followed the first direction indicated. The right-and-left movements involved the crossing of the images. The last four were _both_ to right, to left, up, down. The time was taken with a stop-watch and includes the time between the director's word of command and the subject's report, 'now.' It includes, therefore, two reaction times. The subject reported the instant the colors reached, or appeared at, the suggested positions.

It is to be noticed that H. was very much slower than any of the others in making the movements, both out and back; and that K., while also slower (though much less so than H.) in making the movements outward, was no slower in making the return movements.

TABLE IV.

MOVEMENTS OF TWO IMAGES.

Twenty movements of each kind for each subject. Averages in seconds.

In Opposite Directions.

Subj. L.-R. Ret. R.-L. Ret. U.-D. Ret. D.-U. Ret.

B. 1.82 2.90 2.10 2.27 0.86 0.87 0.73 0.86

G. 3.02 2.86 2.68 2.63 1.98 2.25 1.63 2.01

H. 9.18 10.30 7.50 7.15 5.16 6.90 5.36 5.21

I. 4.17 3.52 3.40 3.37 1.26 1.47 1.23 1.31

J. 2.17 2.90 2.87 2.27 1.05 1.63 1.02 1.13

K. 5.51 6.43 5.16 4.81 1.43 1.48 1.20 1.23

Ave. 4.32 4.82 3.82 3.75 1.96 2.43 1.87 1.96

Average of all movements involving separation (480), 4.18. Returns, 2.06.

In Same Direction.

Subj. R. Ret. L. Ret. U. Ret. D. Ret.

B. 1.31 1.22 1.30 1.11 0.72 0.67 0.72 0.85

G. 2.66 2.35 3.01 2.53 2.00 1.86 2.22 1.86

H. 8.45 7.91 5.66 7.66 6.53 5.95 5.96 6.11

I. 2.57 2.27 2.13 2.05 0.97 1.26 1.00 1.13

J. 1.11 1.16 1.08 11.5 0.68 0.90 0.73 0.71

K. 3.97 3.91 3.60 4.07 1.35 1.50 1.75 1.71

Ave. 3.33 3.14 2.79 3.10 2.04 2.02 2.04 2.06

Average of all movements together (480), 3.09. Returns, 2.04.

NUMERICAL.

There were nineteen hundred and twenty movements in all, including the returns to the original positions.

In the order of difficulty as shown by the time taken, the movements stand as follows, the numbers being the averages in seconds for one hundred and twenty movements of each kind:

1. Right and left (_i.e._, crossing), 4.82 sec.

2. Left and right, 4.32 "

3. Up and down, 3.82 "

4. Down and up, 3.75 "

5. Both right, 3.33 "

6. Both left, 3.14 "

7. Both down, 3.10 "

8. Both up, 3.04 "

SUBJECTIVE.

In the experiments in which the time was recorded, there was no disappearance of either image except where movements were made successively. In these cases frequently the image which was awaiting its turn vanished until the first image was placed, a time varying from a quarter of a second to three or four seconds. Occasionally the image already placed would vanish, while the other was _en route_; the subject's attention in both these cases being centered exclusively on the image he desired to move. This was especially the case when the distances to which the images were moved were great, as to the ends of the room or to ceiling and floor. In other experiments, where, after the movements took place, the images were held for a short time, there were disappearances of one image or the other ranging from one quarter of a second to fifteen seconds, most of the absences, however, being under five seconds. The absences were more numerous in the latter half of the five minutes covered by the experiment. Occasionally a noise in the adjoining room or in the street made the images disappear.