Effects of unembedded time- and event-based prospective memory tasks on an ongoing working memory task.

摘要

The present investigation focused on the relationship between prospective memory (PM) and working memory (WM). The multinomial theory (Smith, 2003) proposes that all PM tasks exert a cost on an ongoing task. The multiprocess theory (Einstein et al., 2005) suggests that the extent of PM cost to the ongoing task depends on the complexity of the PM task, with the provision that some PM tasks can be completed automatically. In an effort to evaluate predictions made by these two theories within a unified experimental setting, the present study investigated the impact of engagement in three types of PM tasks, and assessed the contribution of individual WM capacity in this process.;Participants performed an ongoing WM task under three PM conditions: time-based (TB), event-based (EB), and time-based with reminder (TBR); a control group completed the ongoing task without the PM. Ongoing task performance measures included accuracy and reaction time (RT).;Our results did not provide unequivocal support for either the multiprocess or the multinomial theory. There were no significant difference between the control and the experimental groups, a finding that was complicated by unexpected performance pattern by the control group. However, results indicated that participants in the most demanding condition (TB) were significantly least likely to improve their RT relative to baseline, compared to participants in the least demanding condition (EB), while the TBR group performed in the middle (ns). When aided with a reminder, the TB group performed slower than the EB group but faster than the TB group, suggesting that the reminder effectively alleviated some of the processing cost of he pure time-based PM task. Finally, rate of responding was proportional to individual WM capacity: there was a main effect of WM, with High WM participants performing more accurately and faster on the ongoing task compared to the low WM participants. Notably, WM capacity did not moderate the effect of PM task on the ongoing task performance, with comparable performance patterns observed across the WM capacity spectrum.