Page:Popular Science Monthly Volume 50.djvu/374

358 memory. He had no idea of my purpose but regarded the exercise as a game, a notion which I encouraged by now and then pitting myself against him. Simple as the exercise appears, it afforded a clearer view of Isaiah's mind than speech could possibly have done. Here, at the stage of simple sensation and within the psychic circle that it evolves, he was all alert and responsive. It is difficult for me to convey a clear idea of his awakened activities; I can only sum up what he did in dry statistics, which are meaningless aside from comparison. I should add, with reference to the experiments, that in the absence of apparatus for signaling our expedient was as follows:

At the word now from Isaiah the series presented was covered and the duplicate set of cards placed before him. An assistant, watch in hand, marked the time passed both in examining and placing the cards. I did not caution Isaiah against the use of mnemonic devices, for I judged that he knew none, his range of associations being extremely limited. The experiments were made from twice to three times a week for about five weeks. In three instances, the same series was repeated twice in succession, in every other case a series was presented but once. The summary of results is as follows: Simultaneous presentation, eighteen series, ten colors each; average time for learning each color, five and three fourths seconds (or fifty-seven and a half seconds per series); average time for placing each color, nine and two thirds seconds, or one minute and thirty-six seconds per series; percentage of errors, 36·6. Successive presentations of ten series, ten colors each; average time for observing each color, five and three fifths seconds; average time for placing each color, nine and three fourths seconds; percentage of errors, twenty-nine.

I made occasional essays with aural series—i. e., reading the names of the colors arranged until Isaiah was ready to replace them. Of these I preserved only the following record: Four aural series, ten colors each; average time for learning each color, five and five sevenths seconds; average time for placing each color, six seconds; percentage of errors, fifty.

The experiments having proceeded thus far, I entered upon an educative series. By this means the time for learning a series was reduced to half a minute, and for placing the same, to forty-five seconds, while the percentage of errors fell to sixteen.

In arranging the series the boy's action was slow, and he seemed able to begin indiscrimately at either end or in the middle. Apparently he recalled the colors partly by name; this, however, helped him little, as he did not know the names of shades and neutral tints. I tried having him count, as a means of inhibiting the names when he was examining the cards, but I thought this helped rather than hindered, as the name attached