Fig. 11.
[Figure 12] (Schillings again) is indicative of a low degree of psychic tension. With the very first tap the head begins to rise and continues to do so throughout the test. A true final jerk does not occur, we note rather in all three curves registering the head movements, slight time-marking movements, especially in the second curve. In the third curve they are at first minute, but increase steadily in size until the fourth tap, after which they suddenly disappear. The subject had, as a matter of fact, thought of the number 4, but it is hardly probable that Hans would have reacted properly upon these stimuli.
Fig. 12.
Mr. Schillings had thought of the same number in all three tests given in figures [10], [11] and [12]. The probabilities are that if he had been working with the horse at the time, in the first case Hans would have reacted with three taps with the right foot and a final tap with the left, as a result of the questioner's bending forward again after the premature head-jerk at 3. In the second instance the horse would probably have given four taps with the right foot, and in the third, the chances are that he would have continued to tap beyond the 4.
These curves give, on the whole, a fair idea of the intensity and of the course of attention of the various subjects.
Let us now consider a number of records which illustrate the expressive movements involved in the process of thinking of such concepts as "up", "down", etc. Their arrangement is identical with the scheme given in [figure 5], with the exception that the tapping curves (the sixth and seventh) do not appear. The subject was asked to think of any of the words "up", "down", "right", "left", "yes", "no", etc. He was to begin to conceive them vividly when the command "Now!" was given. This moment is recorded in figures [13] to [15] on the fifth curve. What has been said on [page 123] with regard to respiration, holds also in these instances: only the first rise recorded in [figure 14] can be regarded as normal. The magnitude of these movements varies between ½ and 3 millimeters. The records of the subject whose movements were most extensive, show an average of 1-7/10 millimeter (based on 50 tests), with a mean variation of 6/10 millimeter. Lack of space precludes the reproduction of more than three records.