A wandering mind is a forgetful mind: A systematic review on the influence of mind wandering on episodic memory encoding

Examining the effect of expected test format and test difficulty on the frequency and mnemonic costs of mind wandering

Mind wandering, generally defined as task-unrelated thought, has been shown to constitute between 30% and 50% of individuals' thoughts during almost every activity in which they are engaged. Critically, however, previous research has shown that the demands of a given task can lead to either the up- or down-regulation of mind wandering and that engagement in mind wandering may be differentially detrimental to future memory performance depending on learning conditions. The goal of the current research was to gain a better understanding of how the circumstances surrounding a learning episode affect the frequency with which individuals engage in off-task thought, and the extent to which these differences differentially affect memory performance across different test formats. Specifically, while prior work has manipulated the conditions of encoding, we focused on the anticipated characteristics of the retrieval task, thereby examining whether the anticipation of later demands imposed by the expected test format/difficulty would influence the frequency or performance costs of mind wandering during encoding. Across three experiments, we demonstrate that the anticipation of future test demands, as modelled by expected test format/difficulty, does not affect rates of mind wandering. However, the costs associated with mind wandering do appear to scale with the difficulty of the test. These findings provide important new insights into the impact of off-task thought on future memory performance and constrain our understanding of the strategic regulation of inattention in the context of learning and memory.

Semantic associations restore neural encoding mechanisms

Lapses in attention can negatively impact later memory of an experience. Attention and encoding resources are thought to decline as more experiences are encountered in succession, accounting for the primacy effect in which memory is better for items encountered early compared to late in a study list. However, accessing prior knowledge during study can facilitate subsequent memory, suggesting a potential avenue to counteract this decline. Here, we investigated the extent to which semantic associations-shared meaning between experiences-can counteract declines in encoding resources. Our hypothesis is that semantic associations restore neural encoding mechanisms, which in turn improves memory. We recorded scalp electroencephalography (EEG) while male and female human participants performed a delayed free recall task. Half of the items from late in each study list were semantically associated with an item presented earlier in the list. We find that semantic associations improve memory specifically for late list items and selectively modulate the neural signals engaged during the study of late list items. Relative to other recalled items, late list items that are subsequently semantically clustered-recalled consecutively with their semantic associate-elicit increased high-frequency activity and decreased low-frequency activity, a hallmark of successful encoding. Our findings demonstrate that semantic associations restore neural encoding mechanisms and improve later memory. More broadly, these findings suggest that prior knowledge modulates the orientation of attention to influence encoding mechanisms.

Some young adults hyper-bind too: Attentional control relates to individual differences in hyper-binding

Hyper-binding - the erroneous encoding of target and distractor information into associative pairs in memory - has been described as a unique age effect caused by declines in attentional control. Previous work has found that, on average, young adults do not hyper-bind. However, if hyper-binding is caused by reduced attentional control, then young adults with poor attention regulation should also show evidence of hyper-binding. We tested this question with an individual differences approach, using a battery of attentional control tasks and relating this to individual differences in hyper-binding. Participants (N = 121) completed an implicit associative memory test measuring memory for both target-distractor (i.e., hyper-binding) and target-target pairs, followed by a series of tasks measuring attentional control. Our results show that on average, young adults do not hyper-bind, but as predicted, those with poor attentional control show a larger hyper-binding effect than those with good attentional control. Exploratory analyses also suggest that individual differences in attentional control relate to susceptibility to interference at retrieval. These results support the hypothesis that hyper-binding in older adults is due to age-related declines in attentional control, and demonstrate that hyper-binding may be an issue for any individual with poor attentional control, regardless of age.

Disentangling boredom from depression using the phenomenology and content of involuntary autobiographical memories

Recurrent involuntary autobiographical memories (IAMs) are memories retrieved unintentionally and repetitively. We examined whether the phenomenology and content of recurrent IAMs could differentiate boredom and depression, both of which are characterized by affective dysregulation and spontaneous thought. Participants (n = 2484) described their most frequent IAM and rated its phenomenological properties (e.g., valence). Structural topic modeling, a method of unsupervised machine learning, identified coherent content within the described memories. Boredom proneness was positively correlated with depressive symptoms, and both boredom proneness and depressive symptoms were correlated with more negative recurrent IAMs. Boredom proneness predicted less vivid recurrent IAMs, whereas depressive symptoms predicted more vivid, negative, and emotionally intense ones. Memory content also diverged: topics such as relationship conflicts were positively predicted by depressive symptoms, but negatively predicted by boredom proneness. Phenomenology and content in recurrent IAMs can effectively disambiguate boredom proneness from depressive symptoms in a large sample of undergraduate students from a racially diverse university.

The effect of video playback speed on learning and mind-wandering in younger and older adults

Prior work has demonstrated that watching videos at faster speeds does not significantly impair learning in younger adults; however, it was previously unclear how increased video speed impacts memory in older adults. Additionally, we investigated the effects of increased video speed on mind-wandering. We presented younger and older adults with a pre-recorded video lecture and manipulated the video to play at different speeds. After watching the video, participants predicted their performance on a memory test covering the material from the video and then completed said memory test. We demonstrated that although younger adults can watch lecture videos at faster speeds without significant deficits in memory, older adults' test performance is generally impaired when watching at faster speeds. Additionally, faster playback speeds seem to reduce mind-wandering (and mind-wandering was generally reduced in older adults relative to younger adults), potentially contributing to younger adults' preserved memory at faster speeds. Thus, while younger adults can watch videos at faster speeds without significant consequences, we advise against older adults watching at faster speeds.

The effect of video playback speed on learning and mind-wandering in younger and older adults

Prior work has demonstrated that watching videos at faster speeds does not significantly impair learning in younger adults; however, it was previously unclear how increased video speed impacts memory in older adults. Additionally, we investigated the effects of increased video speed on mind-wandering. We presented younger and older adults with a pre-recorded video lecture and manipulated the video to play at different speeds. After watching the video, participants predicted their performance on a memory test covering the material from the video and then completed said memory test. We demonstrated that although younger adults can watch lecture videos at faster speeds without significant deficits in memory, older adults' test performance is generally impaired when watching at faster speeds. Additionally, faster playback speeds seem to reduce mind-wandering (and mind-wandering was generally reduced in older adults relative to younger adults), potentially contributing to younger adults' preserved memory at faster speeds. Thus, while younger adults can watch videos at faster speeds without significant consequences, we advise against older adults watching at faster speeds.

Self-reported encoding quality promotes lure rejections and false alarms

The hippocampus supports distinctive encoding, enabling discrimination of perceptions from similar memories. Here, an experimental and individual differences approach examined the role of encoding quality in the classification of similar lures. An object recognition task included thought probes during study and similar lures at test. On-task study reports were associated with lure discrimination in within-subject and between-subjects analyses. Within-subject on-task reports were also associated with false classifications of lures as studied objects. These results are compatible with the view that quality encoding supports memory-based rejection of lures but also engenders false alarms when perceptions and memories are inaccurately compared.

Where Is My Mind…? The Link between Mind Wandering and Prospective Memory

Mind wandering (MW) is a common feature of the human experience occurring when our attention shifts from the task at hand to inner thoughts. MW seems to be often future-oriented and could be used to help people to carry out their planned actions (Prospective Memory PM). Here, we tested the link between MW and the ability to perform PM intentions. We assessed MW and PM over 15 days using experience-sampling probes via mobile phone (226 participants) associated with a naturalistic PM task. We confirmed that MW occupies a significant proportion of our mental activity (40%). This time seems to be mainly used to project ourselves into the future (64%), whether to anticipate and imagine the long term (20%) or to plan daily obligations (44%). Intriguingly, only past-oriented thoughts (9%) predict the PM performance. We discuss the possible functional role played by MW in maintaining intentions in mind.

Readiness to remember: predicting variability in episodic memory

Learning and remembering are fundamental to our lives, so what causes us to forget? Answers often highlight preparatory processes that precede learning, as well as mnemonic processes during the act of encoding or retrieval. Importantly, evidence now indicates that preparatory processes that precede retrieval attempts also have powerful influences on memory success or failure. Here, we review recent work from neuroimaging, electroencephalography, pupillometry, and behavioral science to propose an integrative framework of retrieval-period dynamics that explains variance in remembering in the moment and across individuals as a function of interactions among preparatory attention, goal coding, and mnemonic processes. Extending this approach, we consider how a 'readiness to remember' (R2R) framework explains variance in high-level functions of memory and mnemonic disruptions in aging.

Meta-analytic evidence that mindfulness training alters resting state default mode network connectivity

This meta-analysis sought to expand upon neurobiological models of mindfulness through investigation of inherent brain network connectivity outcomes, indexed via resting state functional connectivity (rsFC). We conducted a systematic review and meta-analysis of rsFC as an outcome of mindfulness training (MT) relative to control, with the hypothesis that MT would increase cross-network connectivity between nodes of the Default Mode Network (DMN), Salience Network (SN), and Frontoparietal Control Network (FPCN) as a mechanism of internally-oriented attentional control. Texts were identified from the databases: MEDLINE/PubMed, ERIC, PSYCINFO, ProQuest, Scopus, and Web of Sciences; and were screened for inclusion based on experimental/quasi-experimental trial design and use of mindfulness-based training interventions. RsFC effects were extracted from twelve studies (mindfulness n = 226; control n = 204). Voxel-based meta-analysis revealed significantly greater rsFC (MT > control) between the left middle cingulate (Hedge's g = .234, p = 0.0288, I2 = 15.87), located within the SN, and the posterior cingulate cortex, a focal hub of the DMN. Egger's test for publication bias was nonsignificant, bias = 2.17, p = 0.162. In support of our hypothesis, results suggest that MT targets internetwork (SN-DMN) connectivity implicated in the flexible control of internally-oriented attention.