The first step is to discover the “threshold” of each separate color. That means the smallest-sized hole through which each color can be distinguished. This varies for different colors. But now comes the interesting point. The size of the hole, for any given color seen, varies according to the nature of any sound heard at the same time. For instance, in order to distinguish a given red, the hole must be larger or smaller, in proportion as the pitch of a musical tone is lower or higher, fainter or stronger.
STUDYING THE EFFECTS OF COLORS ON JUDGMENTS OF TIME.
The above experiment is one in a system of investigations, intended to discover the laws by which the simplest sensations modify each other under the simplest conditions. These are laws as fixed as the laws of gravity, and, once determined, we may move on to study the combination of these elements into the higher thought processes.
EFFECTS OF ATTENTION.
Another experiment will further illustrate this method of study. An apparatus is so contrived that a colored disk can be made darker or brighter by the operator, and a measure of the change be recorded. (See illustration on opposite page, rear group.) The persons operated on do not know what change is made, or whether any will be made or not. They first look at the disk for ten seconds, taking good note of its color. Next, the operator changes the shade (or not) as he sees fit. Then for another ten seconds the subject judges the shade of color, but this time performs meanwhile a sum in addition as the operator calls to him simple numbers.
The experiment is to determine how the appearance of the color changes, by reason of dividing the attention between observing the disk and performing the addition. Do the colors of a rival’s bonnet really grow more glaring the harder they are looked at? To explain this is to touch on a social as well as an esthetic problem.