Erdelyi, M. H., & Kleinbard, J. (1978). Has Ebbinghaus decayed with time? The growth of recall (hypermnesia) over days. Journal of Experimental Psychology: Human Learning and Memory, 4(4), 275-289.
http://dx.doi.org/10.1037/0278-7393.4.4.275
Experimental research on memory since H. Ebbinghaus has predominantly focused on the fact of forgetting, creating the impression that memory inevitably decreases with time or time-correlated interpolated events. Recent laboratory work on the recall of pictures, however, has suggested that memory for certain classes of stimuli may be hypermnesic rather than amnesic, increasing over time and recall attempts. The present study attempted to determine the magnitude of memory growth over more significant time intervals. Tests of memory up to 1 wk, in 1 and 6 Ss, indicated substantial growth of recall for pictures, but not usually for words. The outcomes are discussed in terms of (a) their bearing on the Ebbinghaus experimental tradition; (b) the relation of this study to other hypermnesia literature, including P. B. Ballard's reminiscence, hypnotic hypermnesia, memory recoveries in therapy, and the Penfield effect; and (c) the implications of hypermnesia for psychodynamics and unconscious processes. (41 ref) (PsycINFO Database Record (c) 2016 APA, all rights reserved)