Time-of-day variation of visuo-spatial attention

Sleep well, mind wander less: A systematic review of the relationship between sleep outcomes and spontaneous cognition

Despite an upsurge of research on spontaneous cognition, little is known about its associations with sleep-related outcomes. This systematic review, following PRISMA guidelines, examined the relationship between sleep and spontaneous thoughts, across different definitions and measurements of sleep outcomes and spontaneous cognition, and a diversity of methodologies. Twenty-one articles with survey and/or experimental designs were identified. Self-reported disturbed sleep-comprising poor sleep quality, more insomnia symptoms, more daytime sleepiness and a tendency towards eveningness-and experimentally induced sleep deprivation were associated with a tendency to engage in disruptive mind wandering and daydreaming, but not positive-constructive daydreaming. Findings regarding circadian fluctuation in spontaneous thoughts were mixed and inconclusive. This systematic review bridges the gap between the sleep and spontaneous cognition research by contributing to the understanding of potential psychological and cognitive mechanisms of spontaneous cognition, as well as by elucidating the emotional and cognitive consequences of disturbed sleep.

The 3-Minute Psychomotor Vigilance Test Demonstrates Inadequate Convergent Validity Relative to the 10-Minute Psychomotor Vigilance Test Across Sleep Loss and Recovery

The Psychomotor Vigilance Test (PVT) is a widely used behavioral attention measure, with the 10-min (PVT-10) and 3-min (PVT-3) as two commonly used versions. The PVT-3 may be comparable to the PVT-10, though its convergent validity relative to the PVT-10 has not been explicitly assessed. For the first time, we utilized repeated measures correlation (rmcorr) to evaluate intra-individual associations between PVT-10 and PVT-3 versions across total sleep deprivation (TSD), chronic sleep restriction (SR) and multiple consecutive days of recovery. Eighty-three healthy adults (mean ± SD, 34.7 ± 8.9 years; 36 females) received two baseline nights (B1-B2), five SR nights (SR1-SR5), 36 h TSD, and four recovery nights (R1-R4) between sleep loss conditions. The PVT-10 and PVT-3 were completed every 2 h during wakefulness. Rmcorr compared responses on two frequently used, sensitive PVT metrics: reaction time (RT) via response speed (1/RT) and lapses (RT > 500 ms on the PVT-10 and > 355 ms on the PVT-3) by day (e.g., B2), by study phase (e.g., SR1-SR5), and by time point (1000-2000 h). PVT 1/RT correlations were generally stronger than those for lapses. The majority of correlations (48/50 [96%] for PVT lapses and 38/50 [76%] for PVT 1/RT) were values below 0.70, indicating validity issues. Overall, the PVT-3 demonstrated inadequate convergent validity with the "gold standard" PVT-10 across two different types of sleep loss and across extended recovery. Thus, the PVT-3 is not interchangeable with the PVT-10 for assessing behavioral attention performance during sleep loss based on the design of our study and the metrics we evaluated. Our results have substantial implications for design and measure selection in laboratory and applied settings, including those involving sleep deprivation.

School start times and academic achievement - A systematic review on grades and test scores

Early school times clash with the late sleep of adolescents, leading to wide-spread sleep restriction in students. Evidence suggests that delaying school starts is beneficial for sleep and recent studies investigated whether this also translates into improved academic achievement. We thus conducted a systematic review of the literature on school start times, grades and test scores in middle and high-school students. We reviewed 21 studies following the PRISMA guidelines and assessed the evidence quality using a pre-defined risk of bias tool. Nine studies reported no association of later starts with achievement, while the remaining reported mixed (5), positive (5), negative (1) or unclear (1) results. Considering the heterogeneity in academic outcomes, study types, amount of delay and exposure, and the substantial risk of bias, a meta-analysis was not warranted - instead we provide grouped reviews and discussion. Overall, no generalisable improvements in achievement with later starts emerge beyond the level of single studies. This does not necessarily preclude improvements in students' learning but highlights shortcomings of the literature and the challenges of using grades and test scores to operationalise academic achievement. Given other previously reported positive outcomes, our results suggest that schools could start later while achievement is likely maintained.

Sleep duration, sleep variability, and impairments of visual attention

Attentional networks are sensitive to sleep deprivation. However, variation in attentional performance as a function of normal sleep parameters is understudied. We examined whether attentional performance is influenced by (a) individual differences in sleep duration, (b) sleep duration variability, and/or (c) their interaction. A total of 57 healthy participants (61.4% female, M_age = 32.37 years, SD = 8.68) completed questionnaires, wore wrist actigraphy for 1 week, and subsequently completed the attention network test. Sleep duration and sleep duration variability did not predict orienting score, executive control score, or error rates. Sleep duration variability appeared to moderate the association between sleep duration with overall reaction time (β = -.34, t = -2.13, p = .04) and alerting scores (β = .43, t = 2.94, p = .01), though further inspection of the data suggested that these were spurious findings. Time of testing was a significant predictor of alerting score (β = .35, t = 2.96, p = .01), chronotype of orienting (β = .31, t = 2.28, p = .03), and age of overall reaction time (β = .35, t = 2.70, p = .01). Our results highlight the importance of examining the associations between variations in sleep-wake patterns and attentional networks in samples with greater variation in sleep, as well as the importance of rigorously teasing apart mechanisms of the sleep homeostat from those related to the circadian rhythm in studies examining cognition.

Mind-wandering rates fluctuate across the day: evidence from an experience-sampling study

Previous research has demonstrated reliable fluctuations in attentional processes during the course of the day. Everyday life experience sampling, during which participants respond to "probes" delivered at random intervals throughout the day on their mobile devices, is an effective tool for capturing such diurnal fluctuations in a naturalistic way. The existence of diurnal fluctuations in the case of mind-wandering, however, has not been examined to date. We did so in two studies. In the first study, we employed everyday experience sampling to obtain self-reports from 146 university students who rated the degree of free movement in their thoughts multiple times per day over five days. These time course data were analyzed using multilevel modelling. Freely moving thought was found to fluctuate reliably over the course of the day, with lower ratings reported in the early morning and afternoon and higher ratings around midday and evening. In the second study, we replicated these effects with a reanalysis of data from a past everyday experience-sampling study. We also demonstrated differences in parameter values for the models representing freely moving thought and two common conceptualizations of mind-wandering: task-unrelated thought and stimulus-independent thought. Taken together, the present results establish and replicate a complex pattern of change over the course of the day in how freely thought moves, while also providing further evidence that freedom of movement is dissociable from other dimensions of thought such as its task-relatedness and stimulus-dependence. Future research should focus on probing possible mechanisms behind circadian fluctuations of thought dynamics.

The Influence of Alertness on the Spatial Deployment of Visual Attention is Mediated by the Excitability of the Posterior Parietal Cortices

With a reduced level of alertness, healthy individuals typically show a rightward shift when deploying visual attention in space. The impact of alertness on the neural networks governing visuospatial attention is, however, poorly understood. By using a transcranial magnetic stimulation twin-coil approach, the present study aimed at investigating the effects of an alertness manipulation on the excitability of the left and the right posterior parietal cortices (PPCs), crucial nodes of the visuospatial attentional network. Participants’ visuospatial attentional deployment was assessed with a free visual exploration task and concurrent eye tracking. Their alertness level was manipulated through the time of the day, that is, by testing chronotypically defined evening types both during their circadian on- and off-peak times. The results revealed an increased excitability of the left compared with the right PPC during low alertness. On the horizontal dimension, these results were accompanied by a significant rightward shift in the center and a bilateral narrowing in the periphery of the visual exploration field, as well as a central upward shift on the vertical dimension. The findings show that the manipulation of non-spatial attentional aspects (i.e., alertness) can affect visuospatial attentional deployment and modulate the excitability of areas subtending spatial attentional control.

Influence of time-of-day on joint Navon effect

The shared attention theory suggests that people devote greater cognitive resources to those features co-attended simultaneously with others, determining better performance in several types of tasks. When co-actors performed a go/no-go Navon task attending different features of target letters, the performance was impaired, reflecting a joint Navon effect (the representation of a co-actor's attentional focus made it more difficult to select and apply one's own focus of attention), probably due to asynchronous co-attention with a decrease in cognitive resources involved. Researches in chronobiology and chronopsychology demonstrated that not only selective attention (involved in a Navon task), but also cognitive resources have a daily fluctuations, mainly paralleling the circadian rhythm of body temperature (i.e. increasing values from the morning to evening with a subsequent decline in the night). The study was conducted to assess whether the presence of joint attention, as measured by the joint Navon effect, was influenced by the time-of-day. Sixteen pairs of participants sitting next to each other were required to respond to the identity letters in a go/no-go Navon task twice: in the morning (09:00-10:00) and early afternoon (13:00-14:00). The results showed a joint Navon effect in the morning session only, suggesting that joint attention was affected by the time-of-day effect on cognitive resources.

Lower school performance in late chronotypes: underlying factors and mechanisms

Success at school determines future career opportunities. We described a time-of-day specific disparity in school performance between early and late chronotypes. Several studies showed that students with a late chronotype and short sleep duration obtain lower grades, suggesting that early school starting times handicap their performance. How chronotype, sleep duration, and time of day impact school performance is not clear. At a Dutch high school, we collected 40,890 grades obtained in a variety of school subjects over an entire school year. We found that the strength of the effect of chronotype on grades was similar to that of absenteeism, and that late chronotypes were more often absent. The difference in grades between the earliest 20% and the latest 20% of chronotypes corresponds to a drop from the 55^th to 43^rd percentile of grades. In academic subjects using mainly fluid cognition (scientific subjects), the correlation with grades and chronotype was significant while subjects relying on crystallised intelligence (humanistic/linguistic) showed no correlation with chronotype. Based on these and previous results, we can expand our earlier findings concerning exam times: students with a late chronotype are at a disadvantage in exams on scientific subjects, and when they are examined early in the day.