When the mind wanders: Distinguishing stimulus-dependent from stimulus-independent thoughts during incidental encoding in young and older adults.

Abstract

In recent years, several studies have indicated that healthy older adults exhibit a reduction in mind-wandering compared to young adults. However, relatively little research has examined the extent to which ongoing thoughts in young and older adults are dependent on environmental stimuli. In the current study, we assessed age-related differences in frequency of stimulus-dependent thoughts (SDTs) and stimulus-independent thoughts (SITs) during a slow-paced incidental encoding task. Based on previous research suggesting that older adults rely on external information to a greater extent than young adults, we hypothesized that ongoing thoughts in older adults may be more stimulus-dependent than in young adults. We found that although older adults reported overall fewer thoughts compared to young adults, they exhibited a reduction in proportion of SITs and an increase in proportion of SDTs. In both age groups, SDTs were more frequently about the past compared to SITs, while SITs were more frequently about the future. Finally, the extent to which both young and older adults reported SDTs, but not SITs, at encoding was positively correlated with how often they reported remembering thoughts at retrieval, and SDT frequency was positively correlated with overall performance on the memory task in older adults. Our results provide evidence that ongoing thoughts in older adults may be more dependent on environmental stimuli than young adults, and that these thoughts may impact performance in recognition tasks.

Manipulating cues in mind wandering: Verbal cues affect the frequency and the temporal focus of mind wandering

“…The retrospective bias reported in the present study by the Verbal-cues group is consistent with the evidence coming from direct comparisons between involuntary memories and involuntary future thoughts (Berntsen & Jacobsen, 2008): although both involuntary memories and involuntary future events were found to be mainly triggered by clearly identifiable cues, external cues were more frequent for involuntary memories than for involuntary future events (52% vs. 34% in Berntsen & Jacobsen, 2008). In a similar vein, in a very recent study on MW in elderly and young adults, Maillet and Schacter (2016b) found that environmental stimuli (cues) primarily triggered past-oriented thoughts. These results are consistent with the fact that, compared to memories, involuntary future thinking is related to and triggered primarily by current concerns, being less dependent from external stimulation (Cole & Berntsen, 2015;Klinger, 2013).…”

“…Specifically, in the study by Mazzoni et al (2014) more IAMs were elicited when verbal cues were presented during the task, rather than pictorial cues, whereas there was no significant difference between the effects of verbal and pictorial cues on the non-memory contents. As recently suggested by Maillet and Schacter (2016b), the strong association between environmental cues and past-events might be a very important adaptive mechanism that helps people relate the current environment to similar situations experienced in the past and this might support appropriate behavior (Preston & Eichenbaum, 2013).…”

“…Future studies should investigate these effects in other populations of special interest for research on MW, such as elderly people. Studies on aging have shown a reduction in MW in healthy older adults compared to young adults (see for a Running head: Role of verbal cues in mind wandering 22 discussion, Maillet & Schacter, 2016a), and an age-related increase in reliance on the environment (Craik, 1986;Maillet & Schacter, 2016b). Future studies should examine the effects of the exposure to task-irrelevant verbal cues on the frequency and temporal orientation of MW in elderly people and verify whether the presence of external cues might increase the frequency of engagement in MW in elderly people, to a stronger extent than in young adults.…”

Default Network and Aging: Beyond the Task-Negative Perspective

“…For example, whereas current evidence suggests that older adults do not mind-wander more than young adults during cognitive tasks (thoughts that have nothing to with, and were not triggered by any stimulus the current task, such as dinner plans), one possibility is that they exhibit more task-related thoughts and feelings (thoughts/feelings triggered by stimuli in the task itself, such as a picture of a sofa triggering a thought about how it looks similar to the one in my living room) [12]. Distinguishing which thoughts are task-related/unrelated is a thorny issue, and may vary based on the specific requirements of a task.…”

Reduced mind-wandering in mild cognitive impairment: Testing the spontaneous retrieval deficit hypothesis.

“…. Accordingly, Maillet and Schacter (2016b) have made a useful distinction between stimulus-dependent and stimulus independent mind-wandering and have provided initial empirical evidence for potential differences between the two (see Maillet et al, 2017). 5 Consequently, in the present study we have investigated the effects of aMCI status on stimulus-dependent (but spontaneous) mind-wandering, given that instances of stimulusindependent mind-wandering (i.e., instances of task-unrelated thoughts with no reported triggers) were relatively low in both groups.…”