Encoding variability,levels of processing,and the effects of spacing of repetitions upon judgments of frequency

Two experiments were carried out to compare the component-levels theory and the levels-of-processing hypothesis as explanations of the effect the spacing between repetitions of an item has upon the retention of that item. Retention was measured by judgments of frequency, frequency discrimination, and derived recognition scores. Variable encoding contexts facilitated recognition relative to repeated encoding contexts, while the latter biased subjects toward giving high judgments of frequency. The results in general were consonant with predictions derived from a levels-of-processing explanation of the spacing effect rather than the component-levels theory. A modification of the latter theory to incorporate the former was suggested as a view of the memorial representation of repeated stimuli.