The next tables (V. and VI.) give the results of experiments in suppressing one of two images, the objects presented being saturated color squares, discs, triangles, etc., placed side by side, one above the other, or a smaller one superposed on a larger.  The time of perception was five seconds.  After the disappearance of after-images, if there were any, the subject was directed to suppress one of the two memory images, the one to be suppressed being indicated by the director.  The subject reported as soon as the indicated image disappeared, and reported any return of the suppressed image and its later disappearance in consequence of his efforts.  Also he reported any disappearance and reappearance of the retained image.  Five minutes was the limit of the time for the experiments with a few exceptions.  The times were recorded, and those given for the first suppression include the time between the director’s command and the subject’s report ‘now’ or ‘gone,’ and include, therefore, two reaction times.  The later suppressions include but one reaction time.

TABLE V.

SUMMARY OF ALL SUPPRESSIONS.  AVERAGE TIME IN SECONDS.

[Label 1:  Image Suppressed] [Label 2:  No of Exper.] [Label 3:  Time of First Supp.] [Label 4:  Time of Ab. of Supp.  Im.] [Label 5:  No. of Later Supp.] [Label 6:  Time of Later Supp.] [Label 7:  No. of Ab. of Supp.  Im.] [Label 8:  Time of Ab. of Supp.  Im.] [Label 9:  Time of All Supp.] [Label 10:  Time of All Absence of Supp.  Im.]

[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] Right. 46 11.59 82.39 221 8.43 216 35.74 8.94 43.93 Left. 43 11.89 79.34 175 7.79 173 44.86 8.60 51.26 Upper. 22 11.67 49.77 150 6.26 147 29.75 6.95 32.35 Lower. 17 14.23 64 71 7.88 70 46.68 9.11 50.04 Central. 42 18.24 96.93 357 3.90 352 18.13 5.41 26.54 Marginal. 20 14.25 181.57 24 8.93 24 78.08 11.35 125.12 Sundry. 7 8.71 127.21 19 13.34 19 47.27 12.09 68.78 Averages. 13.48 91.25 6.46 32.14 7.60 41.86

TABLE VI

  SUPPRESSIONS GROUPED BY SUBJECTS.  AVERAGE TIME IN SECONDS.

[Label 1:  Subject] [Label 2:  No. of Exp.] [Label 3:  Time of First Supp.] [Label 4:  Time of Ab. of Supp.  Im.] [Label 5:  No. of Later Supp.] [Label 6:  Time of Later Supp.] [Label 7:  No. of Ab. of Supp.  Im.] [Label 8:  Time of Ab. of Supp.  Im.] [Label 9:  Time of All Supp.] [Label 10:  Time of All Ab. of Supp.  Im.]

[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] A. 11 28.32 11.29 117 14.90 114 10.35 16.05 10.44 B. 29 5.79 270.44 5 0.25 5 138.80 4.98 251.08 C. 18 7.88 43.08 64 3.94 63 67.49 4.81 62.07 D. 14 23.28 190.07 6 31.66 5 204.60 25.80 193.89 F. 10 12.67 86.07 230 1.95 230