To what degree are individual differences after a given number of trials indicative of the final maximum capacity of the individuals concerned? At what various rates do the determining factors enter into the practice curves of a group of workers? What manner and amount of displacement in their relative order of ability are thus produced? At what point or points in the curves do the individuals assume their final order of relative capacity after training? How do the replies to these questions vary with the character of the task?

In the case of the experiments already described, record has been here taken of the following points in the curves of practice:

Vocational Psychology: Its Problems and Methods — Part 123

Preliminary trial called initial trial Median of trials 1 to 5 called 5th trial Median of trials 20 to 25 called 25th trial Median of trials 46 to 50 called 50th trial Median of trials 76 to 80 called 80th trial Median of trials 126 to 130 called 130th trial Median of trials 171 to 175 called 175th trial

Vocational Psychology: Its Problems and Methods — Part 123

At each of these points the thirteen subjects were arranged in order of relative ability for the test at the given stage of practice. Each of these orders, or cross sections, of the group of practice curves was then correlated with the final order of position as shown in trials one hundred and seventy to one hundred and seventy-five. Table 24 gives the coefficients of correlation derived in this way. A careful study of this table will prove instructive.

Vocational Psychology: Its Problems and Methods — Part 123

SHOWING THE CORRELATION OF ULTIMATE CAPACITY WITH CAPACITY AT DIFFERENT POINTS IN THE CURVE OF LEARNING

----------------------------------------------------------- | | | | | | |Final The Test |Prelim-| 5th | 25th| 50th| 80th| 130th|Trial | inary |Trial|Trial|Trial|Trial| Trial|175th --------------+-------+-----+-----+-----+-----+------+----- Adding | .15 | .19 | .87 | .87 | .97 | .96 | 1.00 Opposites | -.08 | .62 | .49 | .83 | .94 | .98 | 1.00 Color Naming | .68 | .89 | .86 | .91 | .97 | .97 | 1.00 Discrimination| .68 | .62 | .60 | .50 | .50 | .79 | 1.00 Cancellation | .67 | .68 | .88 | .69 | .93 |(1.00)| -- Coördination | .52 | .79 | .77 | .90 | .95 |(1.00)| -- Tapping | .23 | .48 | .63 | .68 | .69 | .89 | 1.00 |-------+-----+-----+-----+-----+------+----- Averages | .41 | .61 | .73 | .77 | .85 | .92 | 1.00 -----------------------------------------------------------