Of course this statement and the formula upon which it rests have here no other value than that of a shorthand statement of the above results which have been found but once and under the circumstances described. Whether they possess a more general significance so that, under other circumstances or with other individuals, they might find expression in other constants I cannot at the present time say.
Section 30. Control Tests
At any rate, even though only for my own case, I can to a certain extent give support to two of the values mentioned by tests which were made at other periods.
From a period even further back than that of the investigations above mentioned I possess several tests with series of ten syllables, fifteen series composing one test. The series were first memorised and then, at an average of 18 minutes after the first learning, each series was relearned. Six tests had the following results:—
| L | LW | δ | Q[* 1] |
| 848 | 436 | 412 | 57.5 |
| 963 | 535 | 428 | 50.9 |
| 921 | 454 | 467 | 58.5 |
| 879 | 444 | 435 | 57.5 |
| 912 | 443 | 469 | 59.4 |
| 821 | 461 | 360 | 51.6 |
| m=891 | 462 | 429 | 56.0 P.E.m=1 |
| |||
When relearning series of ten syllables each, 18 minutes after the first memorisation, 56 per cent of the work originally expended was therefore saved. The number agrees satisfactorily with the one found above (p. 68) for the relearning of series of syllables of 13 syllables each after 19 minutes, 58 per cent. Also the fact that the latter, notwithstanding the longer interval, is still a little greater, harmonises completely, as will be seen, with the results of the next chapter. According to them, shorter series, when memorised, are forgotten a little more quickly than longer ones.
