Date of Award
Doctor of Philosophy (PhD)
David A. Washburn
According to the Multiprocess Theory (Einstein and McDaniel, 1990), prospective memory is supported by two separate cognitive processes: monitoring and spontaneous retrieval. Successful monitoring during prospective memory tasks requires attention to be divided between separate stimuli and the attention needs to be sustained throughout the course of the task. However, this theoretical account also allows for prospective memory in the absence of monitoring, as in cases where memory is retrieved spontaneously in response to some cue. In the course of this study, support for the Multiprocess Theory has been found. Using a dual-task paradigm, prospective memory targets were displayed during a lexical decision task where participants were required to make a word/nonword decision to letter strings. Prospective memory targets were found using both monitoring and spontaneous retrieval, although displaying the target in the focus of attention or not did not differentially induce monitoring. A small increase from 2% target presentation rates (Experiments 1 through 3) to 3% target presentation rates (Experiment 4) did produce evidence of task interference that reflects monitoring; however, increasing target presentation rates to 5% did not increase reaction times above those found with 3% target presentation rates. Focal prospective memory targets (words) had higher accuracy rates than nonfocal prospective memory targets (words starting with letter "g"). Inhibiting responses to the lexical decision task to respond to prospective memory targets encouraged priorities to shift attention to the lexical decision task and increased the speed of lexical decision responding across the extended task. No evidence was found to support the hypothesis that sustained attention is identical to, or even a significant component of, monitoring. Sustained attention was not necessary to accomplish the prospective memory action, as variables affecting vigilance were not found to influence prospective-memory performance in the extended version of the dual-task paradigm used in this experiment. In Experiment 3, draining attention resources did negatively affect lexical decision reaction times and prospective memory performance with focal targets, but not with nonfocal targets. The strength of the lexical decision task routine was manipulated by varying the number of lexical decision practice trials given before the dual-task in Experiment 5. The strength of the routine did not affect task interference for focal or nonfocal targets. Overall, monitoring did not follow the sustained-attention pattern observed in vigilance. Prospective memory can be performed utilizing both cognitive mechanisms of monitoring and spontaneous retrieval.
Schultz, Natasha B., "The Role of Spontaneous Retrieval, Monitoring and Sustained Attention in Prospective Memory." Dissertation, Georgia State University, 2013.