| Subject W. | ||||||
|---|---|---|---|---|---|---|
| (1) CT=2.0 | (3) CT=2.2 | (5) CT=2.0 | ||||
| 113 | 133 | RRL | RRL | RRL | RRL | |
| S | 3 | 3 | 9 | 20 | 5 | 21 |
| E | 18 | 19 | 25 | 16 | 18 | 14 |
| L | 24 | 28 | 16 | 14 | 17 | 15 |
| Subject P. | ||||||
| (3) CT={ | 1.6 | (5) CT={ | 1.6 | |||
| (1) CT=2.0 | 2.4 | 2.4 | ||||
| 113 | 133 | RRL(1.6) | RLL(2.4) | RRL(1.6) | RLL(2.4) | |
| S | 2 | 16 | 12 | 16 | 15 | 10 |
| E | 38 | 32 | 32 | 21 | 26 | 19 |
| L | 10 | 2 | 6 | 15 | 14 | 21 |
| Subject B. | ||||||
| (1) CT=2.0 | (2) CT=2.0 | (6) CT=2.0 | ||||
| 113 | 133 | 112 | 122 | aab | abb | |
| S | 4 | 21 | 5 | 20 | 7 | 6 |
| E | 23 | 19 | 22 | 24 | 40 | 38 |
| L | 23 | 10 | 23 | 6 | 3 | 6 |
| Subject Hy. | ||||||
| (1) CT=2.0 | (2) CT=2.4 | (1a) CT=2.0 | ||||
| 113 | 133 | 112 | 122 | 113 | 133 | |
| S | 12 | 46 | 17 | 40 | 17 | 31 |
| E | 9 | 2 | 14 | 8 | 9 | 7 |
| L | 29 | 2 | 19 | 2 | 14 | 2 |
In the series designated as (1a) the conditions were the same as in (1), except that the subject abstracted as much as possible from the tactual nature of the stimulations and the position of the fingers. This was undertaken upon the suggestion of the subject that it would be possible to perform the abstraction, and was not repeated on any other subject.
The results are given in Table VI., where the numerals in the headings indicate the localities and changes of stimulation, in accordance with the preceding scheme, and 'S', 'E' and 'L' designate the number of judgments of shorter, equal and longer respectively.
It will be observed that in several cases a CT was introduced in one class which was different from the CT used in the other classes with the same subject. This was not entirely arbitrary. It was found with subject W, for example, that the use of CT = 2.0 in (3) produced judgments of shorter almost entirely in both types. Therefore a CT was found, by trial, which produced a diversity of judgments. The comparison of the different classes is not so obvious under these conditions as it otherwise would be, but is still possible.
The comparison gives results which at first appear quite irregular. These are shown in Table VII. below, where the headings (1)—(3), etc., indicate the classes compared, and in the lines beneath them + indicates that the interval under consideration is estimated as relatively greater (more overestimated or less underestimated) in the second of the two classes than in the first,—indicating the opposite effect. Results for the first interval are given in the line denoted 'first,' and for the second interval in the line denoted 'second.' Thus, the plus sign under (1)—(3) in the first line for subject P indicates that the variation RLL caused the first interval to be overestimated to a greater extent than did the variation 133.
TABLE VII.
| SUBJECT P. | SUBJECT W. | SUBJECT B. | SUBJECT Hy. | |||||
|---|---|---|---|---|---|---|---|---|
| (1)—(3) | (3)—(4) | (1)—(3) | (3)—(5) | (2)—(1) | (6)—(2) | (2)—(1) | ||
| First. | + | - | + | - | - | + | - | |
| Sec. | + | + | - | + | + | + | + | |
The comparisons of (6) and (2), and (1) and (3) confirm the provisional deduction from Table IV., that the introduction of a local change in an interval lengthens it subjectively, but the comparisons of (3) and (5), (3) and (4), and (2) and (1) show apparently that while the amount of the local change influences the lengthening of the interval, it does not vary directly with this latter in all cases, but inversely in the first interval and directly in the second. This is in itself sufficient to demonstrate that the chief factors of the influence of locality-change upon the time interval are connected with the spatial localization of the areas stimulated, but a further consideration strengthens the conclusion and disposes of the apparent anomaly. It will be noticed that in general the decrease in the comparative length of the first interval produced by increasing the spatial change is less than the increase in the comparative length of the second interval produced by a corresponding change. In other words, the disparity between the results for the two types of test is greater, the greater the spatial distance introduced.
The results seem to point to the existence of two distinct factors in the so-called 'constant error' in these cases: first, what we may call the bare constant error, or simply the constant error, which appears when the conditions of stimulation are objectively the same as regards both intervals, and which we must suppose to be present in all other cases; and second, the particular lengthening effect which a change in locality produces upon the interval in which it occurs. These two factors may work in conjunction or in opposition, according to conditions. The bare constant error does not remain exactly the same at all times for any individual and is probably less regular in tactual time than in auditory or in optical time, according to the irregularity actually found and for reasons which will be assigned later.
3. The third group of experiments introduced the factor of variation in intensity of stimulation. By the introduction of a loop in the circuit, containing a rheostat, two strengths of current and consequently of stimulus intensity were obtained, either of which could be employed as desired. One intensity, designated as W, was just strong enough to be perceived distinctly. The other intensity, designated as S, was somewhat stronger than the intensity used in the preceding work.