Dewar et al. further investigated this idea, by introducing experimenter-imposed rehearsal: in between presentations of list words, participants read aloud words from earlier in the list, mimicking a typical rehearsal pattern. This design ensured that D.A. would rehearse earlier list items later in the list. They found that D.A. no longer showed highly suppressed recall of pre-recency items, and that her performance was slightly suppressed across all items, illustrating a universal deficit in her ability to make temporal discriminations. This supports the hypothesis that amnesiacs’ unusual rehearsal technique, rather than selectively impaired LTM, is responsible for the results.
Race et al. (2013) corroborated these data demonstrating the impairment of STM and LTM in amnesiacs, finding that their ability their ability to remember a single face over intervals of either 8 or 15 seconds was impaired. Hence, the results are consistent with the SIMPLE model and the idea of a unitary memory system.