Normal forgetting of verbal lists as a function of their degree of learning

Three experiments, with 276 undergraduates, examined how degree of learning affects normal forgetting. Exp I varied learning of categorized lists and tested retention at 3 intervals (immediately and 1 or 5 days after presentation). Across all measures, study trials affected intercepts but not slopes of forgetting functions. Exp II varied learning of paired-associate lists and tested retention at the same 3 intervals. Across all measures, trials influenced intercepts but not forgetting slopes. Exp III varied learning of sentence lists and tested verbatim and gist memory at the same intervals. Again, trials affected intercepts but not slopes. Results suggest that the forgetting of verbal lists is independent of their degree of learning. No current theories of memory predict these outcomes, but neither does the pattern of results disconfirm any theory. It is argued that present memory theorizing neglects almost entirely the central problem of normal forgetting. (36 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).