The impact of encoding-retrieval perceptual differences on the retrieval-divided attention effect

Previous research has identified asymmetry between implicit encoding and retrieval processes, wherein the priming effect is disrupted by retrieval interference, termed the 'retrieval divided attention (retrieval-DA) effect'. Additionally, numerous studies have indicated that the priming effect is sensitive to variations in the presentation format of stimuli between the encoding and retrieval phases. Given this context, the current study investigated the origins of the 'retrieval-DA effect' by manipulating the perceptual presentation of stimuli. We employed a dual-task paradigm, utilizing an odd-even decision task as the distractor task and a lexical decision task as the memory task. Results from Experiment 1 revealed the presence of the 'retrieval-DA effect' when the dual task was executed during retrieval, irrespective of the consistency of stimuli between the encoding and retrieval phases. In Experiment 2, by intensifying the disparity in stimuli presentation between encoding and retrieval through positional adjustments of the distracting stimulus, we observed that the retrieval-DA effect persisted even amidst heightened perceptual inconsistency. We propose that the retrieval-DA effect on implicit memory arises from competition for attentional resources elicited by dual-task operations, rather than the perceptual disparities in stimuli presentation between encoding and retrieval.