Date of Award
Doctor of Philosophy (PhD)
Mind-wandering (MW) is a universal cognitive process that is prevalent across individuals and in our everyday lives. It is estimated that over 95% of Americans experience MW every day and that ~30% of our everyday thoughts consist of MW. Despite its pervasiveness in our everyday lives, the nature of how MW interacts with other cognitive processes remains a scientific blind spot. Two interrelated issues regarding the nature of MW in the context of healthy aging were ad-dressed across five experiments. First, given the frequency of MW in our everyday lives, it is important to understand if it serves a functional role in cognition or is simply an epiphenomenon of other cognitive processes. Second, a robust yet paradoxical result in the literature has indicated that although both MW and aging are associated with decreased attentional control, older adults frequently report less MW than younger adults. The present dissertation tested the hypotheses that MW may facilitate memory (potentially via consolidation processes) and that age differences in the ability to reactivate episodic memories during MW may contribute to age-related declines in episodic memory.To address these questions, both younger and older adults encoded paired associates, received targeted reactivation cues during an interval filled with a low-demand “Shapes” task which promotes MW, and were tested on their memory for the cued and uncued stimuli from the initial encoding task. Additionally, in each experiment, thought probes were presented during the Shapes task to examine participants’ thought contents. In Experiments 1 and 2, participants encoded picture-sound-word triads and audio cues were presented during the Shapes task. The results from the first two experiments indicated that younger but not older adults were faster to correctly recall cued stimuli as compared to uncued stimuli. In addition, the more an individual reported episodic MW during the Shapes task, the larger cuing effect they produced at recall. Experiment 3 decreased the complexity of the encoded stimuli, by having participants encode simple picture-word cues, and increased the salience of the cues by presenting picture cues in lieu of auditory cues. The results of Experiment 3 showed a robust cuing effect in correct recall response latencies for both younger and older adults, but only a small effect in recall accuracy for older adults. In Experiment 4, the targeted memory reactivation cues were removed to directly examine if the presence of the cues in the previous experiments increased the likelihood of participants reporting episodic MW during the Shapes task. Indeed, a comparison of participants’ thought probe responses across experiments indicated that this was the case for both younger and older adults. Finally, Experiment 5 tested whether these results would extend to a pair-binding recognition paradigm. The results showed a clear effect of cue on recognition response latencies, predominantly for younger adults, but not on accuracy. Overall, these results support the conclusion that reactivation of encoded information during MW episodes may serve as a mechanism of memory consolidation. Furthermore, at least with the more subtle auditory cues, it appeared that older adults were less likely to successfully reactivate encoded information as compared to younger adults, and this may contribute to their decreased episodic memory. The results from these experiments were interpreted within a retrieval facilitation framework wherein the cues serve to reactivate the earlier traces, and this reactivation benefitted retrieval speed for cued items as compared to uncued items.
Chair and Committee
Julie Bugg, Henry L. Roediger, III, Denise Head, Jonathan Peelle,
Nicosia, Jessica, "Targeted Memory Reactivation during Mind-Wandering in Younger and Older Adults" (2021). Arts & Sciences Electronic Theses and Dissertations. 2516.