Editing Spacing effect (section)

=== Encoding variability ===
The encoding variability theory holds that performance on a memory test is determined by the overlap between the available contextual information during the test and the contextual information available during the encoding.<ref>{{Cite book|title=The Foundations of Remembering: Essays in Honor of Henry L. Roediger, III|last=Nairne|first=James|publisher=Psychology Press|year=2007|isbn=9781841694467|location=New York|pages=85}}</ref> According to this view, spaced repetition typically entails some variability in presentation contexts, resulting in a greater number of retrieval cues.  Contrastingly, massed repetitions have limited presentations and therefore fewer retrieval cues. The notion of the efficacy of the increased variability of encoding is supported by the position that the more independent encodings are, the more different types of cues are associated with an item.<ref name=":0">{{Cite book|url=https://books.google.com/books?id=duFHAwAAQBAJ&q=encoding+variability+spacing&pg=PT265|title=Basic Processes of Learning, Cognition, and Motivation|last=Cormier|first=S. M.|date=April 4, 2014|publisher=Psychology Press|isbn=9781317757481|language=en}}</ref>

There are two types of encoding variability theory that address the spacing effect. The first maintains that the spacing effect refers to the changes in the semantic interpretations of items which cause the effect, while the second holds that variability surrounding context is responsible for the spacing effect, not only semantic variability.<ref name=":0" />

To test the encoding variability theory, Bird, Nicholson, and Ringer (1978)<ref>{{Cite journal |last=Bird |first=Charles P. |last2=Nicholson |first2=Angus J. |last3=Ringer |first3=Susan |date=1978 |title=Resistance of the Spacing Effect to Variations in Encoding |url=https://www.jstor.org/stable/1421519 |journal=The American Journal of Psychology |volume=91 |issue=4 |pages=713–721 |doi=10.2307/1421519 |issn=0002-9556|url-access=subscription }}</ref> presented subjects with word lists that either had massed or spaced repetitions. Subjects were asked to perform various "orienting tasks", tasks which require the subject to make a simple judgment about the list item (i.e. pleasant or unpleasant, active or passive). Subjects either performed the same task for each occurrence of a word or a different task for each occurrence. If the encoding variability theory were true, then the case of different orienting tasks ought to provide variable encoding, even for massed repetitions, resulting in a higher rate of recall for massed repetitions than would be expected. The results showed no such effect, providing strong evidence against the importance of encoding variability.