Page:Memory (1913).djvu/58

 The smaller curve of exhibits graphically the arrangement of these numbers. As may be seen, the number of repetitions necessary for learning equally long series was a little larger in the earlier period than in the later one. Because of its uniformity this relation is to be attributed to differences in the experimental conditions, to inaccuracies in the calculations, and perhaps also to the increased training of the later period. The older numbers fall very close to the position of the later ones, and—what is of chief importance—the two curves lie as closely together throughout the short extent of their common course as could be desired for tests separated by 3&frac12; years and unaffected by any presuppositions. There is a high degree of probability, then, in favor of the supposition that the relations of dependence presented in those curves, since they remained constant over a long interval of time, are to be considered as characteristic for the person concerned, although they are, to be sure, only individual.

In order to keep in mind the similarities and differences between sense and nonsense material, I occasionally made tests with the English original of Byron’s “Don Juan.” These results do not properly belong here since I did not vary the length of the amount to be learned each time but memorised on each occasion only separate stanzas. Nevertheless, it is interesting to mention the number of repetitions necessary because of their contrast with the numerical results just given.

There are only seven tests (1884) to be considered, each of which comprised six stanzas. When the latter, each by itself, were learned to the point of the first possible reproduction, an average of 52 repetitions (P.E.$m$ = &plusmn;0.6) was necessary for all six taken together. Thus, each stanza required hardly nine repetitions; or, if the errorless reproduction is abstracted, scarcely eight repetitions.