The ebb and flow of cognitive fatigue.

If you are currently feeling tired, you are not alone: feelings of fatigue are incredibly common. In a recent study, Matthews et al. investigated moment-to-moment fluctuations in fatigue using behavioral experiments and computational modeling. The study offers a precise account of how fatigue waxes (during physical and cognitive effort) and wanes (during rest).

Revisiting the link between the sustained attention to response task (SART) and daily-life cognitive failures.

In this study, we examined the relationship betweenerrors of commissionon theSustained Attention to Response Task(SART)andscores on the Cognitive Failures Questionnaire (CFQ). The goal was to assess theecological validity of the SARTin a sample of people scoring high on fatigue complaints.SART errors of commission were positively associated with CFQ scores and this finding remained after controlling for fatigue level, age, and SART reaction times.Thus, our results generally supported the ecological validity of the SART. However, when examining subsamples separately, we found the association between SART and CFQ only in our subsample of employees, not in our subsample of university students. The three subscales of the CFQ showed the same pattern of findings. Our results imply that, when using the SART to draw conclusions about everyday life, it is crucial to consider the characteristics of one's sample and control for relevant confounding variables.

Why do people sit? A framework for targeted behavior change.

To improve health and wellbeing, it is crucial that people regularly interrupt their sitting. In this paper, we propose a framework for examining and changing sitting behavior that addresses two key steps in the process towards developing effective interventions. First, we suggest that research should move away from its current focus on sitting time, which is an outcome of behavior. Rather, researchers should focus on stand-to-sit and sit-to-stand transitions, which are discrete units of behavior. Second, drawing on goal hierarchy models, we suggest that people rarely engage in stand-to-sit and sit-to-stand transitions for the purpose of being in a sitting or standing position; rather, we suggest that these transitions are means to higher-order goals (e.g., to complete work tasks, to watch television, to eat dinner). To improve adherence to and effectiveness of sitting behavior interventions, intervention designers should aim to increase the frequency of sit-to-stand (and stand-to-sit) transitions. To achieve this aim, intervention designers should capitalize on the higher-order goals that are typically served by these transitions. We suggest four concrete intervention strategies to increase sit-to-stand transitions in congruence with people's everyday goals. We also describe the implications of our framework for theory and methods in sitting behavior research.

Sitting patterns in cardiovascular disease patients compared with healthy controls and impact of cardiac rehabilitation.

PURPOSE: To identify how and when to intervene in cardiovascular disease (CVD) patients' sedentary behavior, we moved beyond studying total volume of sitting and examined sitting patterns. By analyzing the timing of stand-to-sit and sit-to-stand transitions, we compared sitting patterns (a) between CVD patients and healthy controls, and (b) before and after cardiac rehabilitation (CR). METHODS: One hundered twenty nine CVD patients and 117 age-matched healthy controls continuously wore a tri-axial thigh-worn accelerometer for 8 days (>120 000 posture transitions). CVD patients additionally wore the accelerometer directly and 2 months after CR. RESULTS: With later time of the day, both CVD patients and healthy controls sat down sooner (i.e., shorter standing episode before sitting down; HR = 1.01, 95% CI [1.011, 1.015]) and remained seated longer (HR = 0.97, CI [0.966, 0.970]). After more previous physical activity, both groups sat down later (HR = 0.97, CI [0.959, 0.977]), and patients remained seated longer (HR = 0.96; CI [0.950, 0.974]). Immediately and 2-months following CR, patients sat down later (HRpost-CR  = 0.96, CI [0.945, 0.974]; HRfollow-up  = 0.96, CI [0.948, 0.977]) and stood up sooner (HRpost-CR  = 1.04, CI [1.020, 1.051]; HRfollow-up  = 1.03, CI [1.018, 1.050]). These effects were less pronounced with older age, higher BMI, lower sedentary behavior levels, and/or higher physical activity levels at baseline. CONCLUSION: Cardiac rehabilitation programs could be optimized by targeting CVD patients' sit-to-stand transitions, by focusing on high-risk moments for prolonged sitting (i.e., in evenings and after higher-than-usual physical activity) and attending to the needs of specific patient subgroups.

Correction: Protocol of the Healthy Brain Study: An accessible resource for understanding the human brain and how it dynamically and individually operates in its bio-social context.

[This corrects the article DOI: 10.1371/journal.pone.0260952.].

Personality in anaesthesiologists, a systematic review of the literature.

BACKGROUND: As a central part of their job, anaesthesiologists often have to perform demanding tasks under high-stakes conditions. Yet, some anaesthesiologists seem better able to deal with the demands of the profession than others. OBJECTIVES: This review aims to answer the following questions. What are the necessary or desirable qualities of an anaesthesiologist? Which personality traits or characteristics have been found in anaesthesiologists? How does personality relate to job performance and work stress among anaesthesiologists? DESIGN: Systematic review of studies that examined anaesthesiologists' personality or personality characteristics. We performed our synthesis in terms of the five-factor model of personality. DATA SOURCES: The search was conducted in the PubMed, EMBASE and Web of Science databases. Literature was included until December 2020. ELIGIBILITY CRITERIA: We included qualitative and quantitative studies that examined anaesthesiologists' personality; also, we included studies that focused on anaesthesiologists' stress, performance or mental health but only if these topics were examined from the perspective of personality. RESULTS: We included 6 qualitative and 25 quantitative articles. Synthesis of the qualitative articles revealed two classes of desirable technical and nontechnical personality characteristics. Synthesis of the quantitative articles suggested that anaesthesiologists do not essentially differ from other medical specialists. Moreover, our synthesis revealed several personality traits that predict good performance, low stress and good mental health among anaesthesiologists: lower Neuroticism, higher Extraversion, higher Openness and higher Conscientiousness. CONCLUSION: Those personality traits that predict performance, stress or mental health in anaesthesiologists, also predict performance, stress or mental health in other high demand/high stakes environments (both medical and nonmedical). The ideal anaesthesiologist would be lower on Neuroticism, higher on Extraversion and higher on Conscientiousness.

From work stress to disease: A computational model.

In modern society, work stress is highly prevalent. Problematically, work stress can cause disease. To help understand the causal relationship between work stress and disease, we present a computational model of this relationship. That is, drawing from allostatic load theory, we captured the link between work stress and disease in a set of mathematical formulas. With simulation studies, we then examined our model's ability to reproduce key findings from previous empirical research. Specifically, results from Study 1 suggested that our model could accurately reproduce established findings on daily fluctuations in cortisol levels (both on the group level and the individual level). Results from Study 2 suggested that our model could accurately reproduce established findings on the relationship between work stress and cardiovascular disease. Finally, results from Study 3 yielded new predictions about the relationship between workweek configurations (i.e., how working hours are distributed over days) and the subsequent development of disease. Together, our studies suggest a new, computational approach to studying the causal link between work stress and disease. We suggest that this approach is fruitful, as it aids the development of falsifiable theory, and as it opens up new ways of generating predictions about why and when work stress is (un)healthy.

The effect of opportunity costs on mental fatigue in labor/leisure trade-offs.

Most people experience the feeling of mental fatigue on a daily basis. Previous research shows that mental fatigue impacts information processing and decision making. However, the proximal causes of mental fatigue are not yet well understood. In this research, we test the opportunity cost model of mental fatigue, which proposes that people become more fatigued when the next-best alternative to the current task is higher in value. In 4 preregistered experiments (N = 430), participants repeatedly reported their current level of fatigue and chose to perform a paid labor task versus an unpaid leisure task. In Study 1, all participants were offered the same labor/leisure choice. In Studies 2 and 3, we manipulated the opportunity costs of a labor task by varying the value of an alternative leisure task. In Study 4, we manipulated the opportunity costs of a labor task by varying the value of that labor task. In all studies, we found that people were more likely to choose for leisure as they became more fatigued. In Studies 2 through 4, we did not find that the manipulated leisure value influenced the amount of fatigue participants experienced nor the likelihood to choose for leisure. However, in exploratory analyses, in all studies, we found that participants who reported to value the leisure task more got more fatigued during labor and less fatigued during leisure. Collectively, these results provide cautious support for the opportunity cost model, but they also show that cost-benefit analyses relating to labor and leisure tasks are fleeting. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Chronic stress indicated by hair cortisol concentration in anaesthesiologists and its relationship to work experience and emotional intelligence: A cross-sectional biomarker and survey study.

BACKGROUND: Anaesthesia is a stressful medical specialty. The reaction to stress is constituted by behavioural, psychological and physiological components. Chronic physiological stress can have negative consequences for health. OBJECTIVES: First, we hypothesised that chronic physiological stress is higher for both beginning and late-career consultant anaesthesiologists. Second, we hypothesised that individuals high in emotional intelligence endure lower physiological stress. DESIGN: Cross-sectional biomarker and survey study. SETTING: Participants were recruited during the May 2019 annual meeting of the Dutch Anaesthesia Society. PARTICIPANTS: Of the 1348 colleagues who attended the meeting, 184 (70 male/114 female) participated in the study. Of the study participants, 123 (67%) were consultant anaesthesiologists (52 male/71 female) and 61 (33%) were resident anaesthesiologists (18 male/43 female). Exclusion criteria were endocrine disorders and not having enough hair. Also, experience of a recent major life event led to exclusion from analysis of our hypotheses. MAIN OUTCOME MEASURES: Chronic physiological stress was measured by hair cortisol concentration. Emotional intelligence was assessed using a validated Dutch version of the Trait Emotional Intelligence Questionnaire. As secondary measures, psychological sources of stress were assessed using validated Dutch versions of the home-work interference (SWING) and the effort-reward imbalance questionnaires. RESULTS: In support of Hypothesis 1, hair cortisol concentration was highest among early and late-career consultant anaesthesiologists (quadratic effect: b = 45.5, SE = 16.1, t = 2.8, P = 0.006, R2 = 0.14). This nonlinear pattern was not mirrored by self-reported sources of psychological stress. Our results did not support Hypothesis 2; we found no evidence for a relationship between emotional intelligence and physiological stress. CONCLUSION: In the early and later phases of an anaesthesiologist's career, physiological chronic stress is higher than in the middle of the career. However, this physiological response could not be explained from known sources of psychological stress. We discuss these findings against the background of key differences between physiological and psychological stress.

Mind wandering increases linearly with text difficulty.

Although mind wandering during reading is known to be affected by text difficulty, the nature of this relationship is not yet fully understood. To examine this issue, we conducted an experiment in which participants read non-fiction texts that varied along five levels of difficulty under naturalistic conditions. Difficulty levels were determined based on Flesch-Kincaid Grade Levels and verified with Coh-Metrix indices. Mind wandering was measured with thought probes. We predicted that text difficulty and mind wandering have a U-shaped (i.e., quadratic) relationship. Contrary to our expectations, but in line with some prior studies, mind wandering linearly increased with text difficulty. Additionally, text interest moderated the effect of text difficulty on mind wandering. Finally, mind wandering was associated with worse performance on a comprehension test. Together, our findings extend previous work by showing that (a) a linear relationship between difficulty and mind wandering exists during common page-by-page reading of pre-existing texts and that (b) this relationship holds across a broad range of difficulty levels.

Protocol of the Healthy Brain Study: An accessible resource for understanding the human brain and how it dynamically and individually operates in its bio-social context.

The endeavor to understand the human brain has seen more progress in the last few decades than in the previous two millennia. Still, our understanding of how the human brain relates to behavior in the real world and how this link is modulated by biological, social, and environmental factors is limited. To address this, we designed the Healthy Brain Study (HBS), an interdisciplinary, longitudinal, cohort study based on multidimensional, dynamic assessments in both the laboratory and the real world. Here, we describe the rationale and design of the currently ongoing HBS. The HBS is examining a population-based sample of 1,000 healthy participants (age 30-39) who are thoroughly studied across an entire year. Data are collected through cognitive, affective, behavioral, and physiological testing, neuroimaging, bio-sampling, questionnaires, ecological momentary assessment, and real-world assessments using wearable devices. These data will become an accessible resource for the scientific community enabling the next step in understanding the human brain and how it dynamically and individually operates in its bio-social context. An access procedure to the collected data and bio-samples is in place and published on https://www.healthybrainstudy.nl/en/data-and-methods/access. Trail registration: https://www.trialregister.nl/trial/7955.

Fatigue, boredom and objectively measured smartphone use at work.

Nowadays, many people take short breaks with their smartphone at work. The decision whether to continue working or to take a smartphone break is a so-called labour versus leisure decision. Motivational models predict that people are more likely to switch from labour (work) to leisure (smartphone) the more fatigue or boredom they experience. In turn, fatigue and boredom are expected to decrease after the smartphone was used. However, it is not yet clear how smartphone use at work relates to fatigue and boredom. In this study, we tested these relationships in both directions. Participants (n = 83, all PhD candidates) reported their current level of fatigue and boredom every hour at work while an application continuously logged their smartphone use. Results indicate that participants were more likely to interact with their smartphone the more fatigued or bored they were, but that they did not use it for longer when more fatigued or bored. Surprisingly, participants reported increased fatigue and boredom after having used the smartphone (more). While future research is necessary, our results (i) provide real-life evidence for the notion that fatigue and boredom are temporally associated with task disengagement, and (ii) suggest that taking a short break with the smartphone may have phenomenological costs.

Labor/leisure decisions in their natural context: The case of the smartphone.

In this research, we attempt to understand a common real-life labor/leisure decision, i.e., to perform cognitive work or to interact with one's smartphone. In an ecologically valid experiment, participants (N = 112) could freely switch back and forth between doing a 2-back task and interacting with their own smartphone. We manipulated the value of the 2-back task (by varying the value of monetary rewards; within-subjects) and of the smartphone (by switching on and off airplane mode; within-subjects) while we recorded incoming notifications, such as text messages. Our study produced three main findings: (1) the current value of the smartphone did not increase our statistical model's ability to predict switches from labor to leisure when the current task value was also taken into account; (2) however, participants reacted strongly to naturally incoming notifications, which were the strongest predictor of labor-to-leisure switches; (3) there was no evidence that taking into account individual differences (in the value assigned to labor and leisure) improved the model's ability to predict labor-leisure switches. In sum, using a situated approach to studying labor/leisure decisions, our findings highlight the importance of high task motivation, as well as the temporary distractive potential of smartphone notifications, when people face the challenge of staying focused on their productive tasks.

Reward-driven distraction: A meta-analysis.

People have a strong tendency to attend to reward cues, even if these cues are irrelevant to their current goal or their current task. When reward cues are goal-irrelevant, their presence may impair cognitive performance. In this meta-analysis, we quantitatively examined the rapidly growing literature on the impact of reward-related distractors on cognitive performance. We included 91 studies (N = 2,362) that used different cognitive paradigms (e.g., visual search, conflict processing) and reward-related stimuli (e.g., money, attractive food). Overall, results showed that reward-related distractors impaired cognitive performance across different tasks and stimuli, with a small effect size (standardized mean change = .347). Between-study heterogeneity was large, suggesting that researchers can plausibly expect to sometimes find reversed effects (i.e., reward-related distractors boosting performance). We further showed that the average reward-driven distraction effect was robust across different reward-learning mechanisms, contexts, and methodological choices, and that this effect existed regardless of explicit task instructions to ignore distractors. In sum, the findings of this meta-analysis support the notion that cognitive processes can be thwarted by reward cues. We discuss these findings against the background of distraction-related phenomena as they are studied in clinical, educational, and work psychology. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Temporal dynamics of sitting behavior at work.

Sitting for prolonged periods of time impairs people's health. Prior research has mainly investigated sitting behavior on an aggregate level, for example, by analyzing total sitting time per day. By contrast, taking a dynamic approach, here we conceptualize sitting behavior as a continuous chain of sit-to-stand and stand-to-sit transitions. We use multilevel time-to-event analysis to analyze the timing of these transitions. We analyze ∼30,000 objectively measured posture transitions from 156 people during work time. Results indicate that the temporal dynamics of sit-to-stand transitions differ from stand-to-sit transitions, and that people are quicker to switch postures later in the workday, and quicker to stand up after having been more active in the recent hours. We found no evidence for associations with physical fitness. Altogether, these findings provide insights into the origins of people's stand-up and sit-down decisions, show that sitting behavior is fundamentally different from exercise behavior, and provide pointers for the development of interventions.

Explore or reset? Pupil diameter transiently increases in self-chosen switches between cognitive labor and leisure in either direction.

When people invest effort in cognitive work, they often keep an eye open for rewarding alternative activities. Previous research suggests that the norepinephrine (NE) system regulates such trade-offs between exploitation of the current task and exploration of alternative possibilities. We examined the possibility that the NE system is involved in another trade-off, i.e., the trade-off between cognitive labor and leisure. We conducted two pre-registered studies (total N = 62) in which participants freely chose to perform either a paid 2-back task (labor) versus a non-paid task (leisure), while we tracked their pupil diameter-which is an indicator of the state of the NE system. In both studies, consistent with prior work, we found (a) increases in pupil baseline and (b) decreases in pupil dilation when participants switched from labor to leisure. Unexpectedly, we found the same pattern when participants switched from leisure back to labor. Both increases in pupil baseline and decreases in pupil dilation were short-lived. Collectively, these results are more consistent with a role of norepinephrine in reorienting attention and task switching, as suggested by network reset theory, than with a role in motivation, as suggested by adaptive gain theory.

Reward-associated distractors can harm cognitive performance.

When people carry out cognitive tasks, they sometimes suffer from distractions, that is, drops in performance that occur close in time to task-irrelevant stimuli. In this research, we examine how the pursuit of rewards contributes to distractions. In two experiments, participants performed a math task (in which they could earn monetary rewards vs. not) while they were exposed to task-irrelevant stimuli (that were previously associated with monetary rewards vs. not). In Experiment 1, irrelevant cues that were previously associated with rewards (vs. not) impaired performance. In Experiment 2, this effect was only replicated when these reward-associated distractors appeared relatively early during task performance. While the results were thus somewhat mixed, they generally support the idea that reward associations can augment the negative effect of distractors on performance.

The feeling of effort during mental activity.

The feeling of effort is familiar to most, if not all, humans. Prior research shows that the feeling of effort shapes judgments (e.g., of agency) and decisions (e.g., to quit the current task) in various ways, but the proximal causes of the feeling of effort are not well understood. In this research, I address these proximal causes. In particular, I conducted two preregistered experiments in which participants performed a difficult vs. easy cognitive task, while I measured effort-related phenomenology (feeling of effort) and physiology (pupil dilation) on a moment-to-moment basis. In both experiments, difficult tasks increased the feeling of effort; however, this effect could not be explained by concurrent increases in physiological effort. To explain these findings, I suggest that the feeling of effort during mental activity stems from the decision to exert physiological effort, rather than from physiological effort itself.

The implicit power motive predicts decisions in line with perceived instrumentality.

Past research suggests that the implicit power motive (i.e., an unconsciously held motivational disposition to derive pleasure from having impact on others) predicts a preference to interact with individuals having submissive-looking faces. The present research extends this finding by testing whether the relation between the implicit power motive and approaching submissiveness depends on instrumentality. In two experiments, participants were assigned to a group that would ostensibly compete with another group. Within this intergroup context, they were asked to select persons as leaders or members for the in-group or the out-group. Potential leaders and members were displayed as submissive-looking or dominant-looking. Results showed that the implicit power motive predicted decisions favoring dominant-looking persons as in-group leaders, and submissive-looking persons as out-group leaders (Study 1) or in-group members (Study 2). These findings indicate that the tendency for people high in the implicit power motive to approach submissive-looking persons depends on the perceived instrumentality for gaining influence over others.