Page:Memory (1913).djvu/129

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Retention as a Function of Order of Succession

121

(1) The results in the case of learning derived series which had been repeated 16 times on the day previous in their original form were as follows:
A Sum of (I, III, V)	B Sum of (II, IV, VI)	Δ (B-A)
656	522	―134
702	514	―188
603	613	10
450	500	50
662	696	34
560	459	―101
588	603	15
637	593	―44
Av. 607	562	―45 P.E._m=±21

(1) The results of learning derived series which had been repeated 64 times on the day previous in their original form were as follows:
A Sum of (I, III, V)	B Sum of (II, IV, VI)	Δ (B-A)
515	642	127
567	415	―152
626	572	―54
588	560	―28
543	452	―91
539	478	―61
584	599	15
592	604	12
Av. 569	540	―29 P.E._m=±20

The fluctuations of the numbers for the separate experiments are also in this case very great. However, it is evident on the first glance and without further comparison that a strong displacement of the differences to the negative side has taken place. This fact is also expressed by the averages. In contrast with previous results, the series II, IV, VI were learned in somewhat shorter time than series I, III, V.

That this exception rests on mere chance is possible but not very probable. The probable errors, although large, are not large enough to indicate this.

I would sooner fear that it was a case of disturbance of the results through the oft-mentioned source of error, anticipation of the outcome (p.27 ff. and p. 101). During the progress of the experiment I believed with increasing certainty that I could fore-