TABLE V
44 experiments with two subjects.
88 experiments with two subjects.Exposure = 125 sec.
| Simple environment | Complex environment | No tendency | |
| Number of subjects | 2 | 2 | |
| Av. % of difference in favor of | 15.9 | 8.5 |
The results are recorded in Table V. (1) The drift of tendency is toward the group with the more complex environment. No one markedly favors the other group. (2) The notes of the observers indicate that the added strips functioned through their effect upon the apparent area of their group. The observers all found the dimensions increased; but with some, apparently by contrast, the added height brought out sharply the narrowness. One observer found this true in general; another, when the barred group came first. The latter says: "The unbarred group, coming first, appears to reflect its compact character on the barred one, when it comes, so that it does not look so attenuated and strange." Here the image brought over to the second took the width of the second somewhat out of relation to its illusory height, whereas in the reverse order the contrast relation was fully maintained.
III. THE INFLUENCE OF FACTORS PRESENTED IN OTHER SENSE-FIELDS BY THE OBJECTS WHOSE NUMBER IS IN QUESTION
A very simple apparatus was employed. The objects whose number was in question were bright steel balls (3/8 inch) thrown loosely into square black frames, 13 cm. inside, placed side by side on a black-topped table. The experiments were performed in series of 30. The groups were kept equal numerically, with this exception, that into each series were introduced four experiments where the groups were so unequal that the observer could have no question as to the correctness of his judgment and the existence of objective differences. This numerical superiority was given to each group alternately, and judgments on it were, of course, excluded from the results. The actual numbers employed in a series varied between 35 and 60 in accordance with the following scheme:
1. 50 each
2. 45 "
3. 50 "
4. 55 "
5. 60 to 40
6. 50 each
7. 45 "
8. 40 "
9. 45 "
10. 50 "
11. 55 "
12. 60 "
13. 40 to 60
14. 50 each
15. 45 "
16. 40 "
17. 35 "
18. 40 "
19. 45 "
20. 50 "
21. 55 "
22. 60 "
23. 60 to 45
24. 50 each
25. 45 "
26. 50 "
27. 60 "
28. 55 "
29. 50 "
30. 45 to 60
The time of a single exposure—in this case two groups at once—was 3 sec. measured by a stop-watch. As to the arrangement of the balls, care was taken that they should not be massed in one place, but scattered somewhat homogeneously over the space within the frames. The illumination was daylight, so managed that shadows cast by the balls were reduced to a minimum. The observer sat close to the table with the groups directly in front of him. He either kept his eyes closed between experiments or held a small screen before them. Sometimes he merely turned away. The operator worked from the opposite side of the table, taking care to make the necessary noises as little suggestive as possible. The observers agreed that they were not consciously influenced by the manipulation.
The progress of these experiments disclosed an astonishing space-error. So far as was conveniently possible the usual technique of elimination was employed.
1. The Influence of Active Pressure.
In this study the groups were differentiated in this way: With one hand the observer rolled the balls of one group under his fingers, while the other group was presented to vision only. The method of observation consisted in rapidly and lightly rolling the balls under the fingers a few times and then surveying both groups visually for the remainder of the exposure, judgment being given on the visual number.
Evidently there is much that is rough about this procedure. Pressure and kinæsthetic factors are lumped off together; the length of the touch-stimulus was not exactly determined; and there is the possibility that the visual stimulation from the group touched is weakened. To be sure the method prevents any great difference in the latter respect; and if we are guarded in our interpretation, something of interest may be learned.
There appeared to be no convenient way to eliminate the space-error. The right hand was used with the right group and the left with the left. So here again interpretation must be circumspect.