Two case studies of very long-term retention

Ashleigh M Maxcey,Richard C Atkinson,Denis Cousineau,Richard M Shiffrin

doi:10.3758/s13423-021-02002-y

Abstract

Here, we present two case studies of extremely long-term retention. In the first, Richard C. Atkinson (RCA) had learned word sequences during experiments for his dissertation. Sixty-seven years later, RCA relearned the same words either in the original order or in a scrambled order. RCA reported no conscious awareness that the words were those used in the dissertation, but his relearning was considerably better for the words in the original order. In the second case study, Denis Cousineau had searched displays of objects for the presence of a target. The targets and foils had been novel at the beginning of training, and his search rate improved markedly over about 70 sessions. After 22 years, retraining showed retention of much of this gain in rate of search, and the rate was markedly faster than search for new objects with the same structure as the trained set. We consider interpretations of these case studies for our understanding of long-term retention.

Highlights

We present two case studies of extremely long-term retention
The present findings certainly cannot demonstrate that long-term memory is permanent, given that many memories cannot be retrieved after long delays, and given that memories can be modified by retrieval events occurring after original learning (e.g., Loftus et al, 1978; Loftus & Palmer, 1974)
Demonstrations like the present ones, in which originally learned procedures or memories are unlikely to have been used or retrieved for very many years, lend some credence to theories holding that failures of long-term memory for events or procedures that have not been activated for long periods are due to failures of retrieval of records that still exist in memory

Summary

Introduction

We present two case studies of extremely long-term retention. In the first, Richard C. Failures of long-term memory are assumed to be due to retrieval failures (e.g., Shiffrin, 1970) and to processes such as context change and interference (e.g., McGeoch, 1932).

Results

Conclusion