Table 6 shows the general averages by the month for a given individual, and in the sixth column the general average of all the determinations for each reactor. The fourth column in each of the earlier tables shows how much the results of a given day vary from the final general average. All the tables give, at the bottom, group averages whenever the full series is present.
Table 7 gives the number of taps executed in ten seconds at each successive test. The dates are not given in detail, but are the same as those of the reaction tests.
Table 8 gives the monthly averages of taps.
Table 9 presents the results of the steadiness tests.
The three sets of results, namely, those from reaction, tapping, and steadiness, differ from each other. On the whole, the reactions grow longer; the tapping varies, but shows neither decided improvement nor deterioration; while steadiness improves very decidedly.
The comment made on the results obtained with the soldiers applies here so far as the reaction tests are concerned. These tests were not repeated with sufficient frequency to reduce the reaction to automatic performance.
The tapping is such a simple performance that improvement is not to be expected. The absence of any general improvement or deterioration argues for an absence of any general nervous change in the reactors.
The improvement in steadiness is in part at least, probably in very large measure, due to the fact that the subjects became more familiar with the test and approached it with less of the embarrassment which attends a new and unfamiliar test.
The lengthening of the reaction times indicates a less intense concentration of the subject upon the work in hand. The slightest relaxation of attention puts the subject behind in responding to the signal. It was clear to superficial observation, especially in certain individual cases, that the subject was giving less attention in the later experiments. This lack of concentration is not obviously related to the changes in diet. Indeed, the fact that no corresponding falling off appears in the tapping would seem to argue that the lack of attention in the reaction tests was not due to deep-seated nervous conditions, so much as to growing impatience on the part of the reactors with the ordeal of being tested. The tapping experiment is less likely to be affected by lack of interest on the part of the subject, because here the subject is called upon to be constantly active, and there is no such opportunity for attention to lapse as is furnished by the intervals which intervene between successive reactions. The tapping is accordingly perhaps the best series on which to base final judgment as to the nervous condition of the men. Here, there appear the variations which show in any ordinary series, but there is no steady improvement through growing familiarity with the test, nor any laxness of attention to produce relatively unfavorable results.
Mr. Steele and Dr. McAllister are largely responsible for the actual collection of the data on which this report is based.