Age-related differences in mind-wandering in daily life

Measuring mind wandering with experience sampling during task performance: An item response theory investigation

The tendency for individuals to mind wander is often measured using experience sampling methods in which probe questions embedded within computerized cognitive tasks attempt to catch episodes of off-task thought at random intervals during task performance. However, mind-wandering probe questions and response options are often chosen ad hoc and vary between studies with extant little guidance as to the psychometric consequences of these methodological decisions. In the present study, we examined the psychometric properties of several common approaches for assessing mind wandering using methods from item response theory (IRT). IRT latent modeling demonstrated that measurement information was generally distributed across the range of trait estimates according to when probes were presented in time. Probes presented earlier in time provided more information about individuals with greater tendency to mind wandering than probes presented later. Furthermore, mind-wandering ratings made on a continuous scale or using multiple categorical rating options provided more information about individuals' latent mind-wandering tendency - across a broader range of the trait continuum - than ratings dichotomized into on-task and off-task categories. In addition, IRT provided evidence that reports of "task-related thoughts" contribute to the task-focused dimension of the construct continuum, providing justification for studies conceptualizing these responses as a kind of task-related focus. Together, we hope these findings will help guide researchers hoping to maximize the measurement precision of their mind wandering assessment procedures.

Speaking Well and Feeling Good: Age-Related Differences in the Affective Language of Resting State Thought

Despite the prevalence and importance of resting state thought for daily functioning and psychological well-being, it remains unclear how such thoughts differ between young and older adults. Age-related differences in the affective tone of resting state thoughts, including the affective language used to describe them, could be a novel manifestation of the positivity effect, with implications for well-being. To examine this possibility, a total of 77 young adults (M = 24.9 years, 18-35 years) and 74 cognitively normal older adults (M = 68.6 years, 58-83 years) spoke their thoughts freely during a think-aloud paradigm across two studies. The emotional properties of spoken words and participants' retrospective self-reported affective experiences were computed and examined for age differences and relationships with psychological well-being. Study 1, conducted before the start of the COVID-19 pandemic, revealed that older adults exhibited more diversity of positive, but not negative, affectively tinged words compared to young adults and more positive self-reported thoughts. Despite being conducted virtually during the COVID-19 pandemic, study 2 replicated many of study 1's findings, generalizing results across samples and study contexts. In an aggregated analysis of both samples, positive diversity predicted higher well-being beyond other metrics of affective tone, and the relationship between positive diversity and well-being was not moderated by age. Considering that older adults also exhibited higher well-being, these results hint at the possibility that cognitively healthy older adults' propensity to experience more diverse positive concepts during natural periods of restful thought may partly underlie age-related differences in well-being and reveal a novel expression of the positivity effect.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42761-024-00239-z.

Listen up, kids! How mind wandering affects immediate and delayed memory in children

Mind wandering occurs when attention becomes disengaged from the here-and-now and directed toward internally generated thoughts; this is often associated with poorer performance on educationally significant tasks. In this study, 8- to 9-year-old children (N = 60) listened to audio stories embedded with intermittent thought probes that were used to determine if participants' thoughts were on or off task. The key objective was to explore the impact of probe-caught mind wandering on both immediate and delayed memory retention. Children reported being off task approximately 24% of the time. Most inattention episodes were classified as task-unrelated thoughts (i.e., 'pure' instances of mind wandering, 9%) or attentional failures due to distractions (9%). Higher frequency of mind wandering was strongly associated with poorer memory recall, and task-unrelated thoughts strongly predicted how well children could recall components of the audio story both immediately after the task and after a 1-week delay. This study is the first to demonstrate the impact of mind wandering on delayed memory retention in children. Results suggest that exploring mind wandering in the foundational years of schooling could provide the necessary empirical foundation for the development of practical interventions geared toward detecting and refocusing lapses of attention in educational contexts.

EEG complexity measures for detecting mind wandering during video-based learning

This study explores the efficacy of various EEG complexity measures in detecting mind wandering during video-based learning. Employing a modified probe-caught method, we recorded EEG data from participants engaged in viewing educational videos and subsequently focused on the discrimination between mind wandering (MW) and non-MW states. We systematically investigated various EEG complexity metrics, including metrics that reflect a system's regularity like multiscale permutation entropy (MPE), and metrics that reflect a system's dimensionality like detrended fluctuation analysis (DFA). We also compare these features to traditional band power (BP) features. Data augmentation methods and feature selection were applied to optimize detection accuracy. Results show BP features excelled (mean area under the receiver operating characteristic curve (AUC) 0.646) in datasets without eye-movement artifacts, while MPE showed similar performance (mean AUC 0.639) without requiring removal of eye-movement artifacts. Combining all kinds of features improved decoding performance to 0.66 mean AUC. Our findings demonstrate the potential of these complexity metrics in EEG analysis for mind wandering detection, highlighting their practical implications in educational contexts.

Diverse functional interaction driven by control-default network hubs supports creative thinking

Complex cognitive processes, like creative thinking, rely on interactions among multiple neurocognitive processes to generate effective and innovative behaviors on demand, for which the brain's connector hubs play a crucial role. However, the unique contribution of specific hub sets to creative thinking is unknown. Employing three functional magnetic resonance imaging datasets (total N = 1,911), we demonstrate that connector hub sets are organized in a hierarchical manner based on diversity, with "control-default hubs"-which combine regions from the frontoparietal control and default mode networks-positioned at the apex. Specifically, control-default hubs exhibit the most diverse resting-state connectivity profiles and play the most substantial role in facilitating interactions between regions with dissimilar neurocognitive functions, a phenomenon we refer to as "diverse functional interaction". Critically, we found that the involvement of control-default hubs in facilitating diverse functional interaction robustly relates to creativity, explaining both task-induced functional connectivity changes and individual creative performance. Our findings suggest that control-default hubs drive diverse functional interaction in the brain, enabling complex cognition, including creative thinking. We thus uncover a biologically plausible explanation that further elucidates the widely reported contributions of certain frontoparietal control and default mode network regions in creativity studies.

No relationships between frequencies of mind-wandering and perceptual rivalry

Our minds frequently wander from a task at hand. This mind-wandering reflects fluctuations in our cognitive states. The phenomenon of perceptual rivalry, in which one of the mutually exclusive percepts automatically switches to an ambiguous sensory input, is also known as fluctuations in our perceptual states. There may be possible relationships between the mind-wandering and perceptual rivalry, given that physiological responses such as fluctuations in pupil diameter, which is an index of attentional/arousal states, are related to the occurrence of both phenomena. Here, we investigate possible relationships between mind-wandering and perceptual rivalry by combining experimental and questionnaire methods in an online research protocol. In Study 1, we found no statistically significant relationships between subjective mind-wandering tendencies measured by questionnaires and frequencies of perceptual rivalry for Necker-cube or structure-from-motion stimuli. Study 2 replicated the results of Study 1 and further confirmed no statistically significant relationships between behavioral measurements of mind-wandering tendencies estimated by sustained attention to response task and frequencies of perceptual rivalry. These findings suggest that mind-wandering and perceptual rivalry would be based on different mechanisms, possibly higher-level cognitive and lower-level perceptual ones.

Individual differences in the frequency of voluntary & involuntary episodic memories, future thoughts, and counterfactual thoughts

Voluntary and involuntary mental time travel can take the form of episodic memory, episodic future thinking, and episodic counterfactual thinking. This study uses an individual-differences approach to understand why people engage in these forms of mental time travel. The individual-differences variables include trait-level personality, boredom proneness, depression, anxiety, stress, emotion regulation, mindfulness, mind-wandering, positive and negative affect, rumination, optimism, thinking styles, and time perspective. Across two studies, our results indicate that individual differences underlie these forms of mental time travel. The most unique, episodic counterfactual thinking, was alone positively correlated with negative emotionality and negatively correlated with optimism. We also observe differences as a function of voluntariness and discuss these findings in relation to the cognitively demanding nature of constructing future and counterfactual thoughts. We discuss the importance of distinguishing voluntary from involuntary thinking and assessing episodic counterfactual thinking in relation to episodic memory and episodic future thinking.

Task-unrelated thought increases after consumption of COVID-19 and general news

Task-unrelated thoughts (TUTs) are frequent distractions from our everyday tasks, which can reduce productivity and safety during task performance. This necessitates the examination of factors that modulate TUT occurrence in daily life. One factor that has previously been implicated as a source of TUT is personally salient concerns. External factors such as news media serve as cues for these concerns, potentially increasing TUT occurrence. However, this has not been thoroughly examined in everyday life settings. We thus utilized Ecological Momentary Assessment to survey participants throughout the day for ten days, on their TUTs and news consumption in two separate studies. Study 1 focused on the impact of news related to the Coronavirus Disease (COVID-19) pandemic, as a common and global concern. We found that TUT occurrence was significantly predicted by COVID-19 news consumption, such that TUT occurrence increased with COVID-19 news consumption. To extend these findings, we implemented Study 2 using similar methods, but focusing on the consumption of news media in general. TUT occurrence was predicted by general news consumption, with an increase in reports of TUT following consumption of news media in general. We thus extended the association found between TUT and COVID-19-related news in Study 1, to any news topic in Study 2. We speculate that the increase in TUTs was due to heightened salience of current concerns, cued by the news. These findings highlight the importance of considering when we choose to consume news media and the value of examining contextual factors when studying TUTs in daily life.

Predicting response time variability from task and resting-state functional connectivity in the aging brain

Aging is associated with declines in a host of cognitive functions, including attentional control, inhibitory control, episodic memory, processing speed, and executive functioning. Theoretical models attribute the age-related decline in cognitive functioning to deficits in goal maintenance and attentional inhibition. Despite these well-documented declines in executive control resources, older adults endorse fewer episodes of mind-wandering when assessed using task-embedded thought probes. Furthermore, previous work on the neural basis of mind-wandering has mostly focused on young adults with studies predominantly focusing on the activity and connectivity of a select few canonical networks. However, whole-brain functional networks associated with mind-wandering in aging have not yet been characterized. In this study, using response time variability-the trial-to-trial fluctuations in behavioral responses-as an indirect marker of mind-wandering or an "out-of-the-zone" attentional state representing suboptimal behavioral performance, we show that brain-based predictive models of response time variability can be derived from whole-brain task functional connectivity. In contrast, models derived from resting-state functional connectivity alone did not predict individual response time variability. Finally, we show that despite successful within-sample prediction of response time variability, our models did not generalize to predict response time variability in independent cohorts of older adults with resting-state connectivity. Overall, our findings provide evidence for the utility of task-based functional connectivity in predicting individual response time variability in aging. Future research is needed to derive more robust and generalizable models.

Default mode network and neural phase synchronization in healthy aging: A resting state EEG study

Aging is associated with altered brain connectivity within the default mode network (DMN). Although research using functional magnetic resonance imaging has quantified age-related alterations in functional connectivity within this network during resting state, it is less clear how this may be reflected in electrophysiological measures, and how this relates to cognitive performance in older adults. The aim of this study was to quantify age differences in phase synchrony of the DMN during resting state, with particular focus on connectivity between the anterior node (i.e., medial prefrontal cortex, or mPFC) and other associated regions in this network. Electroencephalography was recorded from 55 younger adults (18-30 years, 28 females) and 34 older adults (64-88 years, 16 females) in two resting state conditions (eyes-open and -closed). Source-level functional connectivity was quantified using phase-locking value (PLV) with a spatial filter of six sources of interest, and were subjected to data-driven permutation testing between groups from 1 to 50 Hz. Older adults also completed tests of memory, language, executive functioning, and processing speed. Findings indicated decreased connectivity in the alpha2 range for older than younger adults between the mPFC and other DMN regions including the left angular gyrus and bilateral lateral temporal cortices, the latter of which were associated with lower performance in semantic fluency and executive functioning in older adults. Furthermore, greater PLV in theta and beta bands between the mPFC and posterior cingulate regions was found in older than younger adults. These results suggest age-related changes in DMN functional connectivity are non-uniform and frequency-dependent, and may reflect poorer performance in cognitive domains thought to decline with aging.

Do Attentional Lapses Account for the Worst Performance Rule?

The worst performance rule (WPR) describes the phenomenon that individuals’ slowest responses in a task are often more predictive of their intelligence than their fastest or average responses. To explain this phenomenon, it was previously suggested that occasional lapses of attention during task completion might be associated with particularly slow reaction times. Because less intelligent individuals should experience lapses of attention more frequently, reaction time distribution should be more heavily skewed for them than for more intelligent people. Consequently, the correlation between intelligence and reaction times should increase from the lowest to the highest quantile of the response time distribution. This attentional lapses account has some intuitive appeal, but has not yet been tested empirically. Using a hierarchical modeling approach, we investigated whether the WPR pattern would disappear when including different behavioral, self-report, and neural measurements of attentional lapses as predictors. In a sample of N = 85, we found that attentional lapses accounted for the WPR, but effect sizes of single covariates were mostly small to very small. We replicated these results in a reanalysis of a much larger previously published data set. Our findings render empirical support to the attentional lapses account of the WPR.

The effect of context on mind-wandering in younger and older adults

Older adults report less mind-wandering (MW) during tasks of sustained attention than younger adults. The control failure × current concerns account argues that this is due to age differences in how contexts cue personally relevant task-unrelated thoughts. For older adults, the university laboratory contains few reminders of their current concerns and unfinished goals. For younger adults, however, the university laboratory is more directly tied to their current concerns. Therefore, if the context for triggering current concerns is the critical difference between younger and older adults' reported MW frequencies, then testing the two groups in contexts that equate the salience of self-relevant cues (i.e., their homes) should result in an increase in older but not younger adults' MW rates. The present study directly compared rates of MW and involuntary autobiographical memories (IAMs) in the home versus in the lab for younger and older adults using a within-subjects manipulation of context. Inconsistent with the control failure × current concerns account, no significant reduction in the age-gap in MW was found. Suggesting a lack of cues rather than an abundance of cues elicits MW, participants in both age groups reported more MW in the lab than at home. The number of IAMs recalled did not differ across contexts but was lower in older than younger adults. These findings suggest that a cognitive rather than an environmental mechanism may be behind the reduction in spontaneous cognition in aging.

Mind-Wandering during Personal Music Listening in Everyday Life: Music-Evoked Emotions Predict Thought Valence

Research has shown that mind-wandering, negative mood, and poor wellbeing are closely related, stressing the importance of exploring contexts or tools that can stimulate positive thoughts and images. While music represents a promising option, work on this topic is still scarce with only a few studies published, mainly featuring laboratory or online music listening tasks. Here, I used the experience sampling method for the first time to capture mind-wandering during personal music listening in everyday life, aiming to test for the capacity of music to facilitate beneficial styles of mind-wandering and to explore its experiential characteristics. Twenty-six participants used a smart-phone application that collected reports of thought, mood, and emotion during music listening or other daily-life activities over 10 days. The application was linked to a music playlist, specifically assembled to induce positive and relaxing emotions. Results showed that mind-wandering evoked during music and non-music contexts had overall similar characteristics, although some minor differences were also observed. Most importantly, music-evoked emotions predicted thought valence, thereby indicating music as an effective tool to regulate thoughts via emotion. These findings have important applications for music listening in daily life as well as for the use of music in health interventions.

Age-related changes in ongoing thought relate to external context and individual cognition

Understanding how age-related changes in cognition manifest in the real world is an important goal. One means of capturing these changes involves "experience sampling" participant's self-reported thoughts. Research has shown age-related changes in ongoing thought: e.g., older adults have fewer thoughts unrelated to the here-and-now. However, it is currently unclear how these changes reflect cognitive aging or lifestyle changes. 78 younger adults and 35 older adults rated their thought contents along 20 dimensions and the difficulty of their current activity in their daily lives. They also performed cognitive tasks in the laboratory. In a set of exploratory analyses, we found that older adults spent more time thinking positive, wanted thoughts, particularly in demanding contexts, and less time mind wandering about their future selves. Past-related thought related to episodic memory differently in older and younger adults. These findings inform the use of experience sampling to understand cognitive aging.

The impact of social isolation and changes in work patterns on ongoing thought during the first COVID-19 lockdown in the United Kingdom

The COVID-19 pandemic led to lockdowns in countries across the world, changing the lives of billions of people. The United Kingdom's first national lockdown, for example, restricted people's ability to socialize and work. The current study examined how changes to socializing and working during this lockdown impacted ongoing thought patterns in daily life. We compared the prevalence of thought patterns between two independent real-world, experience-sampling cohorts, collected before and during lockdown. In both samples, young (18 to 35 y) and older (55+ y) participants completed experience-sampling measures five times daily for 7 d. Dimension reduction was applied to these data to identify common "patterns of thought." Linear mixed modeling compared the prevalence of each thought pattern 1) before and during lockdown, 2) in different age groups, and 3) across different social and activity contexts. During lockdown, when people were alone, social thinking was reduced, but on the rare occasions when social interactions were possible, we observed a greater increase in social thinking than prelockdown. Furthermore, lockdown was associated with a reduction in future-directed problem solving, but this thought pattern was reinstated when individuals engaged in work. Therefore, our study suggests that the lockdown led to significant changes in ongoing thought patterns in daily life and that these changes were associated with changes to our daily routine that occurred during lockdown.

Cognitive and non-cognitive variables influencing age-related effect of mind wandering across the adult life span

This study aimed to assess the effects of aging on mind wandering (MW) using a sustained attention to response task (SART) with a low cognitive demand. All task-unrelated thoughts (TUTs) and the subcategory of stimulus-independent thoughts (SITUTs) were examined across the adult life span. The relationship between MW, cognitive variables (attention, inhibition, working memory), and non-cognitive variables (mindfulness, psychological well-being, and anxiety) was investigated. The sample included 210 healthy participants from 20 to 89 years old. The overall results showed few or no age-related changes in both TUTs and SITUTs. Path analyses revealed that the effect of age on both TUTs and SITUTs was only indirect and mediated by attentional resources, as well as by some aspects of psychological well-being (i.e., emotional competence), which had a direct effect, however. These findings raise doubts about any age-related differences between young and older adults’ MW. Changes in MW across the adult life span are thus discussed along with the method and tasks used to assess it and different variables affecting it.

Personality and Mind-Wandering Self-Perception: The Role of Meta-Awareness

Mind-wandering is a psychological process involving the emergence of spontaneous thoughts in daily life. Research has shown that mind-wandering influences diverse psychological outcomes; however, less is known about possible individual differences that may drive mind-wandering. In this study, we argue that personality traits, expressed in neuroticism and openness to experience, may lead to the individual's self-perception of their mind-wandering activity, due to meta-awareness processes. In a three-wave survey study with 273 college students, we gathered data which supported a positive association of both neuroticism and openness to experience with mind-wandering self-perception, mediated by the individual's meta-awareness. Thus, this study contributes to the literature on spontaneous thinking by showing that mind-wandering processes may be a function of individual differences expressed in personality traits.

Automating creativity assessment with SemDis: An open platform for computing semantic distance

Creativity research requires assessing the quality of ideas and products. In practice, conducting creativity research often involves asking several human raters to judge participants' responses to creativity tasks, such as judging the novelty of ideas from the alternate uses task (AUT). Although such subjective scoring methods have proved useful, they have two inherent limitations-labor cost (raters typically code thousands of responses) and subjectivity (raters vary on their perceptions and preferences)-raising classic psychometric threats to reliability and validity. We sought to address the limitations of subjective scoring by capitalizing on recent developments in automated scoring of verbal creativity via semantic distance, a computational method that uses natural language processing to quantify the semantic relatedness of texts. In five studies, we compare the top performing semantic models (e.g., GloVe, continuous bag of words) previously shown to have the highest correspondence to human relatedness judgements. We assessed these semantic models in relation to human creativity ratings from a canonical verbal creativity task (AUT; Studies 1-3) and novelty/creativity ratings from two word association tasks (Studies 4-5). We find that a latent semantic distance factor-comprised of the common variance from five semantic models-reliably and strongly predicts human creativity and novelty ratings across a range of creativity tasks. We also replicate an established experimental effect in the creativity literature (i.e., the serial order effect) and show that semantic distance correlates with other creativity measures, demonstrating convergent validity. We provide an open platform to efficiently compute semantic distance, including tutorials and documentation ( https://osf.io/gz4fc/ ).

Mind-Wandering in Adolescents Predicts Worse Affect and Is Linked to Aberrant Default Mode Network-Salience Network Connectivity

OBJECTIVE

Understanding the fluctuating emotional and cognitive states of adolescents with depressive symptoms requires fine-grained and naturalistic measurements. This study used ecological momentary assessment (EMA) to investigate the affective correlates and consequences of mind-wandering in adolescents with anhedonia (AH) and typically developing (TD) controls. In addition, we examined the association between mind-wandering and resting state functional connectivity between the medial prefrontal cortex (mPFC), a core hub of the default mode network (DMN) linked to internally oriented mentation, and networks linked to attentional control (dorsal attention network [DAN]) and affect/salience detection (salience network [SN]).

METHOD

A total of 65 adolescents, aged 12 to 18 years (TD = 36; AH = 29), completed a resting state functional magnetic resonance imaging scan and subsequently used a smartphone application for ecological momentary assessment (EMA) data collection (2-3 times/d for 5 days). Each survey (N = 678) prompted adolescents to report on their current positive and negative affect (PA and NA), cognition, and activity.

RESULTS

The frequency of mind-wandering was higher for AH (70.0% of EMA samples) relative to TD (59.2%) participants, and the participants with AH were more likely to mind-wander to unpleasant content. Mind-wandering was associated with higher concurrent NA, even when controlling for plausible confounds (eg, current activity, social companion, rumination). Time-lagged analyses revealed a bidirectional association between mind-wandering and PA. Greater levels of mind-wandering within the AH group were associated with stronger mPFC-SN/DAN connectivity.

CONCLUSION

Rates of mind-wandering were high, especially among adolescents with anhedonia, and predicted worse affect. The relation between mind-wandering and enhanced mPFC-SN coupling may reflect heightened bottom-up influence of affective and sensory salience on DMN-mediated internally oriented thought.

Older adults show a higher heartbeat-evoked potential than young adults and a negative association with everyday metacognition

The ability to monitor internal bodily and cognitive processes is essential for everyday functioning and independence in older adults, because it allows for adjustments when lapses in performance are imminent. In the present study, age-related morphological changes to the heartbeat evoked potential (HEP), an electrophysiological cortical representation of cardiac signals, and its association with self-reported everyday cognition were examined. A community sample of older adults showed an increased HEP amplitude, which could reflect a stronger representation of early stages of cardiac interoception, and a more anterior scalp distribution of the HEP, suggesting a more widespread configuration of the underlying neural generators, compared to a group of young adults. Furthermore, in older adults, HEP amplitude was negatively correlated with self-estimated everyday cognitive functioning. Older adults with pronounced cortical representations of peripheral signals may thus be more likely to take note of lapses in their own bodily and cognitive function, leading to lower estimates of their cognitive abilities. These results provide novel insights into age-related changes in interoceptive processing and their association with metacognitive judgments, with potentially far-reaching implications for cognitive aging and age-related cognitive decline.

Alterations in resting-state network dynamics along the Alzheimer's disease continuum

Human brain activity is intrinsically organized into resting-state networks (RSNs) that transiently activate or deactivate at the sub-second timescale. Few neuroimaging studies have addressed how Alzheimer's disease (AD) affects these fast temporal brain dynamics, and how they relate to the cognitive, structural and metabolic abnormalities characterizing AD. We aimed at closing this gap by investigating both brain structure and function using magnetoencephalography (MEG) and hybrid positron emission tomography-magnetic resonance (PET/MR) in 10 healthy elders, 10 patients with subjective cognitive decline (SCD), 10 patients with amnestic mild cognitive impairment (aMCI) and 10 patients with typical Alzheimer's disease with dementia (AD). The fast activation/deactivation state dynamics of RSNs were assessed using hidden Markov modeling (HMM) of power envelope fluctuations at rest measured with MEG. Correlations were sought between temporal properties of HMM states and participants' cognitive test scores, whole hippocampal grey matter volume and regional brain glucose metabolism. The posterior default-mode network (DMN) was less often activated and for shorter durations in AD patients than matched healthy elders. No significant difference was found in patients with SCD or aMCI. The time spent by participants in the activated posterior DMN state did not correlate significantly with cognitive scores, nor with the whole hippocampal volume. However, it correlated positively with the regional glucose consumption in the right dorsolateral prefrontal cortex (DLPFC). AD patients present alterations of posterior DMN power activation dynamics at rest that identify an additional electrophysiological correlate of AD-related synaptic and neural dysfunction. The right DLPFC may play a causal role in the activation of the posterior DMN, possibly linked to the occurrence of mind wandering episodes. As such, these data might suggest a neural correlate of the decrease in mind wandering episodes reported in pathological aging.

Comparing the phenomenological qualities of stimulus-independent thought, stimulus-dependent thought and dreams using experience sampling

Humans spend a considerable portion of their lives engaged in 'stimulus-independent thoughts' (SIT), or mental activity that occurs independently of input from the immediate external environment. Although such SITs are, by definition, different from thoughts that are driven by stimuli in one's external environment (i.e. stimulus-dependent thoughts; SDTs), at times, the phenomenology of these two types of thought appears to be deceptively similar. But how similar are they? We address this question by comparing the content of two types of SIT (dreaming and waking SITs) with the content of SDTs. In this 7 day, smartphone-based experience-sampling procedure, participants were intermittently probed during the day and night to indicate whether their current thoughts were stimulus dependent or stimulus independent. They then responded to content-based items indexing the qualitative aspects of their experience (e.g. My thoughts were jumping from topic to topic). Results indicate substantial distinctiveness between these three types of thought: significant differences between at least two of the three mental states were found across every measured variable. Implications are discussed. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.

The psychological correlates of distinct neural states occurring during wakeful rest

When unoccupied by an explicit external task, humans engage in a wide range of different types of self-generated thinking. These are often unrelated to the immediate environment and have unique psychological features. Although contemporary perspectives on ongoing thought recognise the heterogeneity of these self-generated states, we lack both a clear understanding of how to classify the specific states, and how they can be mapped empirically. In the current study, we capitalise on advances in machine learning that allow continuous neural data to be divided into a set of distinct temporally re-occurring patterns, or states. We applied this technique to a large set of resting state data in which we also acquired retrospective descriptions of the participants' experiences during the scan. We found that two of the identified states were predictive of patterns of thinking at rest. One state highlighted a pattern of neural activity commonly seen during demanding tasks, and the time individuals spent in this state was associated with descriptions of experience focused on problem solving in the future. A second state was associated with patterns of activity that are commonly seen under less demanding conditions, and the time spent in it was linked to reports of intrusive thoughts about the past. Finally, we found that these two neural states tended to fall at either end of a neural hierarchy that is thought to reflect the brain's response to cognitive demands. Together, these results demonstrate that approaches which take advantage of time-varying changes in neural function can play an important role in understanding the repertoire of self-generated states. Moreover, they establish that important features of self-generated ongoing experience are related to variation along a similar vein to those seen when the brain responds to cognitive task demands.

Changes in electrophysiological static and dynamic human brain functional architecture from childhood to late adulthood

This magnetoencephalography study aimed at characterizing age-related changes in resting-state functional brain organization from mid-childhood to late adulthood. We investigated neuromagnetic brain activity at rest in 105 participants divided into three age groups: children (6-9 years), young adults (18-34 years) and healthy elders (53-78 years). The effects of age on static resting-state functional brain integration were assessed using band-limited power envelope correlation, whereas those on transient functional brain dynamics were disclosed using hidden Markov modeling of power envelope activity. Brain development from childhood to adulthood came with (1) a strengthening of functional integration within and between resting-state networks and (2) an increased temporal stability of transient (100-300 ms lifetime) and recurrent states of network activation or deactivation mainly encompassing lateral or medial associative neocortical areas. Healthy aging was characterized by decreased static resting-state functional integration and dynamic stability within the primary visual network. These results based on electrophysiological measurements free of neurovascular biases suggest that functional brain integration mainly evolves during brain development, with limited changes in healthy aging. These novel electrophysiological insights into human brain functional architecture across the lifespan pave the way for future clinical studies investigating how brain disorders affect brain development or healthy aging.

Validity of attention self-reports in younger and older adults

Human attention is subject to fluctuations. Mind-wandering (MW) - attending to thoughts unrelated to the current task demands - is considered a ubiquitous experience. According to the Control Failure x Concerns view (McVay & Kane, 2010), MW is curbed by executive control, and task-irrelevant thoughts enter consciousness due to attentional control lapses. The generation of off-task thoughts is assumed to increase with higher number of personal concerns. Challenging this view, older adults report less MW than younger adults. Here, we addressed the hypothesis that older adults report less MW due to a lower ability to notice attention lapses and to appraise their current on-task focus. In an age-comparative study (N = 40 younger and N = 44 older adults) using a battery of three tasks spanning working memory, reading comprehension, and sustained attention, we assessed the correlation between the degree of self-reported on-task focus and task performance on a trial-by-trial basis. Younger and older adults' degree of on-task attention measured through thought probes was correlated equally strongly with performance across trials in all tasks, indicating preserved ability to monitor attentional fluctuations in healthy aging. Self-reported current concerns' number and importance did not differ across age, and they did not predict self-reported attention across tasks. Our study shows that lower rates of MW in aging do not reflect lower validity of older adults' attentional appraisal or lower levels of current concerns.

Differential effects of mind-wandering and visual distraction on age-related changes in neuro-electric brain activity and variability

Optimal performance in many tasks requires minimizing the impact of both visual distractors in the environment and distracting internal thoughts (i.e., mind-wandering). Prior research has indicated that older adults are disproportionately affected by the presence of visual distractors compared to young adults, but are not excessively affected by distracting thoughts. Yet an explanation for these dissociable effects remains elusive. In the current study, we assessed age-related differences in event-related potentials and neural variability associated with internal distraction and visual distractors in a go/no-go task. Compared to young adults, older adults showed an increased visual distraction cost in mean reaction time (RT) and RT variability but a reduction in internal distraction frequency and a reduced internal distraction cost on go accuracy and RT variability. Visual distraction and internal distraction were associated with opposite patterns of behavioral and neural effects. Behaviorally, across age groups, internal distraction was associated with more no-go errors whereas visual distraction was associated with reduced no-go errors. Across groups, internal distraction was associated with decreased P3 amplitude, whereas visual distraction was associated with increased P3 amplitude. In addition, internal distraction was associated with an increase in neural variability (more so in young versus older adults), while visual distraction was associated with a reduction in variability in young adults only. We suggest that the opposing effects of the two distractor types on behavioral and neural measures occur because visual distraction is associated with increased attentional resources devoted to the task to overcome visual interference whereas internal distraction is associated with decreased attentional resources devoted to the task. Moreover, older adults exhibited reduced flexibility of neural variability as a function of both distractor types, which may correspond to a diminished ability to up-regulate attention in the face of visual distraction and a diminished shift in attention away from the task during internal distraction.

Mind-wandering, depression, anxiety and ADHD: Disentangling the relationship

BACKGROUND

Mind Wandering (MW) has been associated with ADHD in a very small number of studies with adults and children. However, anxiety and depression have also been associated with MW and both are often comorbid with ADHD. The aim of this study was to investigate the role of anxiety and depression in MW in patients with ADHD.

METHODS

The Mind Excessively Wandering Scale (MEWS) compared the levels of MW controlling for the presence of anxiety and depression symptoms in 78 adolescents (53 males and 25 females) comprising ADHD, clinical controls and typically developing individuals. Correlational analysis between MEWS score, demographic variables, ADHD, anxiety and depressive symptoms was performed using simple and multiple linear regression analysis demonstrating that only anxiety predicted MW scores. On a second analysis, we compared Anxiety and Non-Anxiety as well as ADHD and non-ADHD groups.

RESULTS

Levels of MW were significantly correlated with anxiety symptoms, but not with depression. In addition, there were no differences in ADHD and non-ADHD groups regarding MW levels.

CONCLUSIONS

Our results suggest MW is associated with anxiety levels, independently of an ADHD diagnosis.

Mind-Wandering Changes in Dysphoria

Changes in mind-wandering (MW) and involuntary autobiographical memory (IAM) in dysphoria have been explored with conflicting results. The aim of this study was to evaluate both MW and IAM in a group of 23 stable dysphoric participants compared to 37 controls and to compare their thoughts characteristics (i.e., specificity, visual perspective, time orientation, and emotional valence). To make this study comparable with previous research, we used two different monotonous vigilance tasks (with and without verbal interference stimuli). Our results showed a significantly greater focus on MW thoughts in dysphoria. The characteristics of spontaneous thoughts content did not differ significantly between our dysphoric participants and controls, which is not in favor of strong emotional dysfunction. Our results suggest a difficulty to regulate the occurrence of self-generated thoughts rather than their content, that may confer to dysphoric subjects increased cognitive risk to develop a major depressive episode.

Aging and the wandering brain: Age-related differences in the neural correlates of stimulus-independent thoughts

In recent years, several studies have indicated that healthy older adults exhibit a reduction in task-unrelated thoughts compared to young adults. However, much less is known regarding age-related differences in time spent engaging in stimulus-independent thoughts or in their neural correlates in the absence of an ongoing task. In the current study, we collected functional magnetic resonance imaging (fMRI) data while 29 young (mean age = 22y) and 22 older (mean age = 70y) adults underwent experience sampling in the absence of an ongoing task (i.e., at “rest”). Although both age groups reported spending a similar amount of time engaged in stimulus-independent thoughts, older adults rated their thoughts as more present-oriented (rather than atemporal) and more novel. Moreover, controlling for these age-related differences in content, we found that experiencing stimulus-independent thoughts was associated with increased posterior cingulate and left angular gyrus activation across age groups compared to exhibiting an external focus of attention. When experiencing stimulus-independent thoughts, younger adults engaged medial and left lateral prefrontal cortex as well as left superior temporal gyrus to a greater degree than older adults. Taken together, our results suggest that, in the absence of an ongoing task, although young and older adults spend a similar amount of time engaging in stimulus-independent thoughts, the content and neural correlates of these thoughts differ with age.

Spontaneous future cognition: the past, present and future of an emerging topic

In this Editorial, we discuss the past, present and future of an emerging and fast-developing field-spontaneous future cognition. In tracking the past of this research, the trajectories of research on mind-wandering, episodic future thinking and prospective memory are briefly examined, and their relation with spontaneous future cognition demarcated. Three broad methodological approaches (questionnaire, naturalistic and laboratory) used to study spontaneous future thoughts are described, providing an overview of the field. The present state of this research is represented by a themed analysis of the articles included in this Special Issue. The breadth of studies (covering cognitive mechanisms, developmental stages and psychopathology) have already led to important insights, especially concerning the conditions in which spontaneous future thoughts most commonly arise and who may be predisposed to experiencing them. In the future, greater effort should focus on developing a theoretical account of spontaneous future cognition-this may increase our understanding of how and why spontaneous future thoughts occur. If future research in this area reflects the diversity and depth within this Special Issue, a flourishing of research on spontaneous future cognition will be on the horizon in years or perhaps decades to come.

Attention, mindwandering, and mood

We tested the hypothesis that mindwandering and external distraction are both manifestations of a common state of reduced attention focus, and examined how both relate to reported level of happiness. We conducted real-time sampling of people's experience of mindwandering, irrelevant distraction (e.g. by music, phone, etc.), and happiness levels, in two studies with 524 people undertaking common daily-life activities. All irrelevant external distractions were positively correlated with mindwandering. Indeed mindwandering duration could be predicted from the reported duration of external distraction, when controlling for a range of background variables. An exploratory factor analysis of mindwandering and distraction reports suggested a single underlying construct. In addition, duration of irrelevant distraction by both mobile phones and mindwandering was significantly associated with reduced reported levels of happiness. The results are consistent with the hypothesis that that a state of reduced attention focus underlies both mindwandering and distractibility and clarify the link with happiness.

Self-Referential Memory Encoding and Mind- Wandering in Younger and Older Adults

Self-referencing, the relating of information to oneself, is a successful encoding strategy that improves memory across the lifespan. Mind-wandering, the shifting of thoughts from a task to selffocused information, is characterised by decreased cognitive performance and is reported by older adults less frequently than by younger adults. In the present study, we investigated a hypothetical relationship between mind-wandering and self-referential memory and whether this relationship decouples in healthy aging. Younger and older adults rated adjectives on how descriptive they were of themselves, Albert Einstein or assessed the commonness of the adjective. Participants were interrupted during the encoding task with randomly timed mind-wandering prompts and then completed a surprise free recall test. Results replicated prior demonstrations of enhanced memory for self-referenced information, whereas age and self-focus decreased reports of mind-wandering. In terms of effects of interest, we found that encoding condition as well as age impacted the number of words recalled and reports of mind-wandering. However, a single mechanism does not appear to account for both of these effects, and there was no compelling evidence for age differences in the relationships amongst the factors. Future research should further examine the relationships amongst self, memory, and mind-wandering across the lifespan.

Age-related changes in the temporal focus and self-referential content of spontaneous cognition during periods of low cognitive demand

An intriguing aspect of human cognition is the unique capacity to mentally retreat from our immediate surroundings to consider perspectives distinct from the here and now. Despite increasing interest in this phenomenon, relatively little is known regarding age-related changes in off-task, self-generated thought (often referred to as "mind-wandering"), particularly under conditions of low cognitive demand. While a number of studies have investigated the temporal orientation of mind-wandering with increasing age, findings have been largely inconsistent. Here, we explored the frequency, temporal focus, and self-referential/social content of spontaneous task-unrelated, perceptually decoupled thought in 30 young and 33 healthy older adults using the Shape Expectations task, a validated experimental paradigm in which discrete facets of inner mentation are quantified along a conceptual continuum using open-ended report. Participants also completed the daydreaming subscale of the Imaginal Process Inventory (IPI) as a trait measure of mind-wandering propensity. Significant group differences emerged on the Shape Expectations task, with reduced instances of mind-wandering in the context of elevated task-related thoughts relative to younger adults. In terms of temporal focus, a preponderance of present/atemporal off-task thoughts was evident irrespective of group; however, significantly higher levels of future-oriented thoughts were provided by younger adults, contrasting with significantly higher instances of retrospection in the older group. In addition, older adults displayed significantly fewer incidences of self-referential cognition relative to their younger counterparts. Our findings indicate a distinct attenuation of off-task, self-generated thought processes with increasing age, with evidence for a shift in temporal focus and self-referential quality, during periods of low cognitive demand.