FIG. 2. Reënforcement-Inhibition curves for momentary auditory stimulation, based upon amount of reaction. Male No. 1 —— Male No. 3 ....
FIG. 3. Reënforcement-Inhibition curves for momentary auditory stimulation, based upon amount of reaction. Female No. 2 —— Female No. 4 ....
The curves are all plotted by the method which will now be described in connection with Fig. 2. This figure presents the reënforcement-inhibition curves for the males No. 1 (solid line in the figure) and No. 3 (broken line). If in this figure we let the zero-point on the ordinates represent the value of the reaction to the tactual stimulus when given alone, then the value of the reaction to the auditory-tactual stimuli would be represented at some point above the zero-point if this reaction was greater than the tactual reaction (reënforcement), and below the zero-point if the reaction was less than the tactual (inhibition). Since one of our chosen measures of reënforcement and inhibition is the amount, in per cent of tactual reaction, by which the auditory-tactual reaction exceeds or falls short of the tactual reaction, such a curve of reënforcement-inhibition as that of Fig. 2 (solid line) can be constructed at once from the data given in column four of Table 3. Here the auditory stimulus, when simultaneous with the tactual, caused 62% reënforcement, as is indicated in the figure. The figures in the left-hand margin of the curves indicate amount of reënforcement or inhibition in per cent of tactual reaction; those at the bottom of the curves mark the intervals. On the curves dots indicate the intervals used in the experiments. Each of the curves is plotted on the basis of 700 reactions.
FIG. 4. Reënforcement-Inhibition curves for momentary auditory stimulation, based upon number of reactions. Male No. 1. —— Male No. 3 ....
FIG. 5. Reënforcement-Inhibition curves for momentary auditory stimulation, based upon number of reactions. Female No. 2 —— Female No. 4 ....
In every way comparable with the curves for the males No. 1 and No. 3 in Fig. 2 are those for the females No. 2 and No. 4 of Fig. 3. The similarity of the two curves in each figure is noteworthy. Inasmuch as the conditions of experimentation were the same for all the animals this would seem to indicate sex-differences which are worthy of further investigation. The curves show clearly the greater reënforcement in the males, and the greater inhibition in the females.
Figures 4 and 5 are the reënforcement-inhibition curves for the same series of experiments plotted on the basis of the number of reactions in excess of half that were reënforced or inhibited. As there were fifty pairs of reactions with each frog for each interval, uniform reënforcement would be represented by twenty-five reactions above the base-line; uniform inhibition by twenty-five reactions below the base-line. The number of reactions is indicated by the figures in the left margin; the intervals, by those below the base-line. As an illustration of the application of the method of plotting, the curve for male No. 1 (solid line) of Fig. 4 is constructed from the data of column five of Table 3. With simultaneous stimuli 17 reactions in excess of half, i. e., 17 + 25, or 42, were reënforced; at .35˝ interval .5 of a reaction was the average amount of reënforcement; at .45˝ interval 10 reactions in excess of half, i. e., 35, were inhibited, therefore the curve falls to 10 below the base-line.