The experiments with these lines were continued at intervals through a number of weeks, each individual average representing the result of ten observations, or of five pairs of exposures with alternating objects.

The striking feature in the observations is the uniformity of the results as they appear in the general averages and in the averages for each pair as shown at the foot of the columns.  There is some variation in the individual tendencies, as shown by the individual averages.  But the general average for this group of subjects shows a difference of less than half a second per minute, and that difference is in favor of the vertical line.

This series will serve a double purpose.  It shows, in the first place, that on the whole the vertical and the horizontal lines have a nearly equal chance of recurrence in image or idea.  It will serve, in the second place, as a standard of comparison when we come to consider the effect of variations in the position and direction of lines.

TABLE XI.

1           2           3           4           5       Indiv.  Av. 
F     O     F     O     F     O     F     O     F     O     F     O
I. 24    31    26.5  28.5  27    29    22    33.5  27.5  28    25.4  30.0
II. 53.5  50    52.5  52.5  56.5  55.5  43.5  43.5  56    51.5  52.4  50.6
III.  3    21.5   4    20    11    17     3.5  27     0    20.5   4.3  21.2
IV. 26.5  30    11    48.5  12.5  53    12    51    23    51    17.0  46.7
V. 40.5  56.5  48    56    55.5  55.5  53    55.5  53.5  55.5  50.1  55.58
VI. 27.5  40.5  23    31.5  24.5  32.5  31    29    27    33.5  26.6  33.4
VII. 50.5  54    53.5  56.5  53.5  53.5  40.5  52    55    55    50.6  54.2
VIII.  1    33.5  11    27     5    32     7.5  39     4.5  36.5   5.8  33.6
IX. 35.5  41.5  45.5  47    41.5  41.5  39    44.5  41    41.5  40.5  43.2
X. 19    30.5  21.5  30.5  21    29.5  16    37.5  22.5  30.5  20.0  31.7
XI. 11.5  52.5  18    51.5  14.5  50.5  23    50.5  15    52.5  16.4  51.5
26.59 40.14 28.59 40.86 29.32 40.86 26.45 42.09 29.55 41.45 28.10 41.08

    F:  Full-faced. O:  Outlined.

    General average:  full-faced, 28.10 sec.; outlined, 41.08 sec.

Series No.  XI.—­In this series full-faced figures were compared with outline figures of the same dimensions and form.  Material, granite-gray cardboard.  The area of the full-faced figures was the same as that of the figures of similar character employed in the various series, approximately 42 sq. cm.; the breadth of the lines in the outline figures was half a centimeter.  The objects in each pair were exposed simultaneously, with the usual instructions to the subject, namely, to regard each object directly, and to give to each the same share of attention as to the other.