The present series of studies investigated the hypothesis that the reduced initiative to allocate attentional resources to relevant tasks underlies depression-related prospective memory (PM) deficits (i.e., cognitive initiative hypothesis). Specifically, in the first three studies, the performance of individuals with high and low depressive symptomatology (HDS and LDS respectively) was examined under a series of PM paradigms (the Memory for Intentions Screening Test [MIST], a laboratory time-based PM task, and a laboratory event-based PM task), with the strategic demands of the PM task systematically manipulated on key variables such as cue type (i.e., time-based, event-based), length of delay interval (i.e., 2 minute versus 15 minute), and task importance (PM task relative to ongoing task). To further evaluate the attentional mechanisms underlying depression related PM deficits, the time-based and event-based studies (Studies 2 & 3) compared HDS and LDS groups on the pattern of decrements to ongoing task performance as a result of PM task performance (i.e., costs in the form of longer response times). The amount of incurred costs was assumed to reflect the extent of cognitive resources voluntarily allocated to the PM task (i.e., cognitive initiative). Collectively, the findings from these three studies suggest that (1) PM performance in individuals with HDS is negatively impacted by strategically demanding PM tasks, (2) these deficits are associated with inefficiencies in the utilization of allocated attentional resources in event-based tasks, and (3) individuals with HDS are less inclined to initiate the internal control processes crucial to the successful completion of time-based PM tasks. In view of the findings of the first three studies, a fourth study investigated whether implementation intentions (i.e., an encoding strategy which purportedly reduces the strategic demands of PM tasks) and goal maintenance training (GMT; a strategy which encourages intermittent self-initiated goal reviews) assist with the attentional function and PM performance of HDS and LDS individuals. Importantly, the study showed that the attention allocation and PM performance of HDS individuals benefitted from implementation intentions and GMT compared to standard PM instructions and that these benefits occurred to the same extent as LDS individuals. Based on the overall findings from the four studies, it was concluded that reduced cognitive initiative do contribute to PM deficits in HDS. However, PM deficits appear to be more likely under certain conditions (e.g., long delay intervals, time-based PM tasks, and important event-based PM tasks) than others (e.g., short delay intervals, unimportant event-based PM tasks, and non-focal event-based PM tasks).
|Qualification||Doctor of Philosophy|
|Publication status||Unpublished - 2014|