The presence of the objective images having been shown to be an aid in the case of series of nouns, the subjects were henceforth requested to obtain them in the noun and verb series of the B and C sets, and the image records show that they were entirely successful in doing so.

2.  The total number of couplets in any one or in several sets may be divided into two classes:  (1) Those in which indirect associations did not occur in the learning, and (2) those in which they did occur.  For reasons already named we may call the first pure material and the second mixed.  We can then ascertain in each the proportion of correctly recalled couplets after one, two, nine and sixteen days’ interval, and thus see the importance of indirect associations as a factor in recall.  This is what has been done in the following table.

The figures give the number of couplets correctly or incorrectly recalled out of 64.  In the case of the interval of one day the figures are a tabulation of the III. test (twenty-one hours) of the C set, which contained 16 series of 4 couplets each.  The figures for the intervals of two, nine and sixteen days are a tabulation of the B set, which also contained 16 series of 4 couplets each. C denotes correct, I incorrect.

TABLE VIII.

SHOWING GREATER PERMANENCE OF COUPLETS IN WHICH INDIRECT ASSOCIATIONS OCCURRED.

Pure Material.                      Mixed Material. 
Days.      One.      Two.    Nine.  Sixteen.    One.    Two.    Nine.  Sixteen. 
C   I    C   I   C   I   C   I   C   I   C   I   C   I   C   I
M.    40  22   23  39  22  40           2   0   2   0   3   0
Mo.   36  22   31  27  29  29           6   0   6   0   5   1
S.    27  34    6  55   2  59   1  60   2   1   3   0   3   0   3   0
Hu.   35  22   16  45   5  56   4  57   6   1   3   0   3   0   3   0
B.    48  16   17  43   9  51   7  53   0   0   4   0   1   3   1   3
Ho.   37  15   17  30  13  36   3  46  10   2   9   6   8   7   7   8

Total:  147  87  132 217  83 268  66 285  18   4  27   6  23  10  21  12
P’c’t.:  63  37   38  62  24  76  19  81  82  18  82  18  70  30  64  36

We see from the table that the likelihood of recalling couplets in which indirect associations did not occur in learning is 63 per cent. after one day, and that there is a diminution of 44 per cent. in the next fifteen days.  The fall is greatest during the second day.  On the other hand, the likelihood of recalling couplets in which indirect associations did occur is 82 per cent. after one day, and there is a diminution of only 18 per cent. during the next fifteen days.  The fading is also much more gradual.

It is evident, then, that in all investigations dealing with language material the factor of indirect associations—­a largely accidental factor affecting varying amounts of the total material (in these six subjects from 3 per cent. to 23 per cent.) is by far the most influential of all the factors, and any investigations which have heretofore failed to isolate it are not conclusive as to other factors.