Harvard Psychological Studies, Volume 1 / Containing Sixteen Experimental Investigations from the Harvard Psychological Laboratory.

by Unknown

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 brass 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.

	From Blue.						From Green.
Subject.	To Green.	Return to Blue.	To Yellow.	Return to Blue.	To Red.	Return to Blue.	To Blue.	Return to Green.	To Yellow.	Return to Green.	To Red	Return to Green.
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

	From Yellow.						From Red.
Subject.	To Blue.	Return to Yellow.	To Green.	Return to Yellow.	To Red.	Return to Yellow.	To Blue.	Return to Red.	To Green.	Return to Red.	To Yellow.	Return to Red.
B.	1.79	1.06	1.35	0.87	1.89	1.10	1.54	0.58	1.71	0.62	1.31	0.71
G.	1.50	1.10	1.48	0.87	1.31	0.88	1.33	0.92	1.35	0.91	0.77	0.58
H.	5.02	4.54	5.73	3.91	6.15	4.17	6.35	3.91	5.89	4.69	5.54	4.37
I.	2.29	1.31	2.54	1.19	2.29	1.27	2.85	1.10	2.50	1.21	1.65	1.31
J.	1.35	0.98	1.35	0.65	1.27	0.88	1.42	1.04	1.31	1.02	1.25	0.85
K.	3.02	1.52	3.21	2.04	2.23	1.79	2.54	1.56	2.66	1.60	2.88	1.81
Av.	2.49	1.76	2.61	1.59	2.52	1.68	2.67	1.51	2.57	1.68	2.23	1.62

TABLE III.

CHANGES TO THE FOUR COLORS.
Average time in seconds. 72 changes from and 72 changes to each color.