Inhibition during task switching is affected by the number of competing tasks.

Inhibition during task switching is assumed to be indexed by n - 2 repetition costs-that is, performance costs when the task in the current trial equals the task in trial n - 2 (sequences of type ABA) compared with two consecutive switches to another task each (sequences CBA). The present study examined effects of a short-term reduction of the number of candidate tasks on these costs. For this purpose, a variant of the task switching paradigm was used in which in half of the trials, a precue that preceded the task cue allowed for a short-term reduction of the number of candidate tasks. In Experiment 1, one out of three tasks could be excluded. In Experiment 2, one or two out of four tasks could be excluded. Experiment 3 served as control condition using the standard cueing paradigm. Significant n - 2 repetition costs were present with three candidate tasks. In contrast, no costs were visible when the number of candidate tasks was reduced to two. This result is interpreted in terms of a task selection mechanism based on antagonistic constraints among task representations, which operates on a rather superficial level when switching among only two tasks, thereby reducing the need for inhibition.

A Systematic Analysis of Biological, Sociodemographic, Psychosocial, and Lifestyle Factors Contributing to Work Ability Across the Working Life Span: Cross-sectional Study.

BACKGROUND: As employees age, their physical and mental abilities decline and work ability decreases, enhancing the risk for long-term sick leave or even premature retirement. However, the relative impact of biological and environmental determinants on work ability with increasing age is poorly understood in terms of their complexity. OBJECTIVE: Previous research has shown relationships between work ability and job and individual resources, as well as specific demographic and lifestyle-related variables. However, other potentially important predictors of work ability remain unexplored, such as personality traits and biological determinants, including cardiovascular, metabolic, immunological, and cognitive abilities or psychosocial factors. Our aim was to systematically evaluate a wide range of factors to extract the most crucial predictors of low and high work ability across the working life span. METHODS: As part of the Dortmund Vital Study, 494 participants from different occupational sectors, aged between 20 and 69 years, completed the Work Ability Index (WAI) assessing employee's mental and physical resources. A total of 30 sociodemographic variables were grouped into 4 categories (social relationships, nutrition and stimulants, education and lifestyle, and work related), and 80 biological and environmental variables were grouped into 8 domains (anthropometric, cardiovascular, metabolic, immunologic, personality, cognitive, stress related, and quality of life) and have been related to the WAI. RESULTS: Using the analyses, we extracted important sociodemographic factors influencing work ability, such as education, social activities, or sleep quality, and identified age-dependent and age-independent determinants of work ability. Regression models explained up to 52% of the WAI variance. Negative predictors of work ability were chronological and immunological age, immunological inefficiency, BMI, neuroticism, psychosocial stress, emotional exhaustion, demands from work, daily cognitive failures, subclinical depression, and burnout symptoms. Positive predictors were maximum heart rate during ergometry, normal blood pressure, hemoglobin and monocyte concentration, weekly physical activity, commitment to the company, pressure to succeed, and good quality of life. CONCLUSIONS: The identified biological and environmental risk factors allowed us to evaluate work ability in its complexity. Policy makers, employers, and occupational safety and health personnel should consider the modifiable risk factors we identified to promote healthy aging at work through focused physical, dietary, cognitive, and stress-reduced preventive programs, in addition to well-balanced working conditions. This may also increase the quality of life, commitment to the job, and motivation to succeed, which are important factors to maintain or even enhance work ability in the aging workforce and to prevent early retirement. TRIAL REGISTRATION: ClinicalTrials.gov NCT05155397; https://clinicaltrials.gov/ct2/show/NCT05155397. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/32352.

Effects of a dynamically changing response set overlap on n - 2 repetition costs.

N - 2 repetition costs are a marker for inhibition processes during task switching that are supposed to reduce interference from currently irrelevant information. The present study aimed at elucidating effects of response set overlap on n - 2 repetition costs while keeping stimulus set overlap constant. For this purpose, each task was associated with two different response sets. The relevant response set was visually cued in every trial. N - 2 repetition costs were present when the response set overlapped from trial n - 2 to trial n - 1. In contrast, they were abolished when the response set switched. This result is interpreted in terms of stronger interference for overlapping response sets that need to be inhibited to a high degree, resulting in large n - 2 repetition costs. Furthermore, the present results support the notion that two means for interference reduction, task inhibition and task shielding, are deployed in a flexible way depending on environmental demands.

Impact of Biological and Lifestyle Factors on Cognitive Aging and Work Ability in the Dortmund Vital Study: Protocol of an Interdisciplinary, Cross-sectional, and Longitudinal Study.

BACKGROUND: Previous research revealed several biological and environmental factors modulating cognitive functioning over a human's lifespan. However, the relationships and interactions between biological factors (eg, genetic polymorphisms, immunological parameters, metabolic products, or infectious diseases) and environmental factors (eg, lifestyle, physical activity, nutrition, and work type or stress at work) as well as their impact on cognitive functions across the lifespan are still poorly understood with respect to their complexity. OBJECTIVE: The goal of the Dortmund Vital Study is to validate previous hypotheses as well as generate and validate new hypotheses about the relationships among aging, working conditions, genetic makeup, stress, metabolic functions, the cardiovascular system, the immune system, and mental performance over the human lifespan with a focus on healthy working adults. The Dortmund Vital Study is a multidisciplinary study involving the Departments of Ergonomics, Immunology, Psychology and Neurosciences, and Toxicology at the Leibniz Research Centre for Working Environment and Human Factors at the Technical University of Dortmund (IfADo) in Germany, as well as several national and international partners. METHODS: The Dortmund Vital Study is designed as a combined cross-sectional and longitudinal study. Approximately 600 healthy subjects aged between 20 and 70 years will participate. A wide range of demographic, psychological, behavioral, sensory, cardiovascular, immunological, and biochemical data, a comprehensive electroencephalography (EEG)-based cognitive test battery as well as structural and functional magnetic resonance imaging (MRI) have been included in the study. RESULTS: The study was approved by the Ethics Committee of IfADo in October 2015. The baseline testing was conducted between 2016 and 2021 and will be repeated every 5 years (3 follow-up measures until 2035). As of March 2020 (until the outbreak of the COVID-19 pandemic), 593 participants have been enrolled. Some results from the cross-sectional part of the study were already published, further results will be published soon. Longitudinal data will be analyzed and published by 2025. CONCLUSIONS: We anticipate that the study will shed light on sources of interindividual differences in the alterations of cognitive functioning with increasing age and reveal biological and lifestyle markers contributing to work ability, longevity, and healthy aging on the one hand, and to risk factors for cognitive decline, mild cognitive impairment, or even dementia on the other hand. TRIAL REGISTRATION: ClinicalTrials.gov NCT05155397; https://clinicaltrials.gov/ct2/show/NCT05155397. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/32352.

No-go trials in task switching: effects on the task-set and task-space level.

A common marker for inhibition processes in task switching are n - 2 repetition costs. The present study aimed at elucidating effects of no-go trials on n - 2 repetition costs. In contrast to the previous studies, no-go trials were associated with only one of the three tasks in the present two experiments. High n - 2 repetition costs occurred if the no-go task had to be executed in trial n - 2, irrespective of whether a response had to be withheld or not. In contrast, no n - 2 repetition costs were visible if the other two tasks were relevant in n - 2. Whereas this n - 2 effect was unaffected by whether participants could reliably exclude a no-go trial or not, effects of no-gos in trial n were determined by this knowledge. The results differ from effects of no-go trials that are not bound to a specific task. It is assumed that the present no-go variation exerted its effect not on the response level, but on the level of task sets, resulting in enhanced salience of the no-go task that leads to higher activation and, as a consequence, to stronger inhibition. The dissociation of the effects on no-gos in trials n - 2 and n as a function of foreknowledge suggests that the balance between activation and inhibition is shifted not only for single trials and tasks, but for the whole task space.

Stimulus-Response Conflict Tasks and Their Use in Clinical Psychology.

This article reviews the historical usage of the concept of 'conflict' in psychology and delineates the design and development of three basic conflict tasks (Stroop, Flanker, Stop Signal). Afterwards, important theoretical concepts to account for conflict processing are introduced. In the second part, the usage of these tasks in clinical psychology is considered. The article closes with some reflections regarding factors that may have been hitherto largely neglected in this respect.

COVID-19 Pandemic and Personality: Agreeable People Are More Stressed by the Feeling of Missing.

The COVID-19 pandemic and the measures taken to contain it have substantial consequences for many people, resulting in negative effects on individual well-being and mental health. In the current study, we examined whether individual changes in perceived stress relative to pre-pandemic levels depended on differences in behavior, appraisal, and experience of pandemic-related constraints. In addition, we tested whether this potential relationship was moderated by personality traits. We conducted an online survey during the end of the first lockdown in Germany in spring 2020, and assessed pandemic-related individual consequences as well as perceived stress. These data were related to the big five personality traits and to ratings of perceived stress obtained from the same participants in a study conducted before the outbreak of the pandemic, using the same standardized stress questionnaires. There was no overall increase, but a large interindividual variety in perceived stress relative to pre-pandemic levels. Increased stress was associated especially with strong feelings of missing. This relationship was moderated by agreeableness, with more agreeable people showing a higher association of the feeling of missing and the increase of perceived stress. In addition, openness and conscientiousness were positively correlated with an increase in stress. The results highlight the importance of considering personality and individual appraisals when examining the consequences of the COVID-19 pandemic on perceived stress and well-being.

Cognitive Capacity, Representation, and Instruction.

The central argument of the present article is that Cognitive Psychology's problems in dealing with the concept of "cognitive capacity" is intimately linked with Cognitive Psychology's long-lasting failure of coming to terms with the concept of "representation" in general, and "task representation" in particular. From this perspective, the role of instructions in psychological experiments is emphasised. It is argued that both a careful conceptual analysis of instruction-induced task representations as well as an experimental variation of instructions promises to broaden our understanding of the role of task representations as a determinant of limited cognitive capacity.

Having to Work from Home: Basic Needs, Well-Being, and Motivation.

During the COVID-19 pandemic, many employees were asked to start working from home for an extended time. The current study investigated how well employees worked and felt in this novel situation by following n = 199 German employees-56% of them female, 24% with childcare duties-over the course of two working weeks in which they reported once daily on their well-being (PANAS-20, detachment) and motivation (work engagement, flow). Participants reported on organizational and personal resources (emotional exhaustion, emotion regulation, segmentation preference, role clarity, job control, social support). Importantly, they indicated how well their work-related basic needs, i.e., autonomy, competence, and relatedness, were met when working from home and how these needs had been met in the office. Multilevel models of growth showed that work engagement, flow, affect and detachment were on average positive and improving over the two weeks in study. Higher competence need satisfaction predicted better daily work engagement, flow, and affect. In a network model, we explored associations and dynamics between daily variables. Overall, the results suggest that people adapted well to the novel situation, with their motivation and well-being indicators showing adequate levels and increasing trajectories. Avenues for improving work from home are job control and social support.

Further investigating effects of task repetition proportion on n - 2 repetition costs: Task shielding as a potential modulating factor?

Previous research has shown that n - 2 repetition costs are reduced when the experimental procedure allows for task repetitions. The present study aimed to further elucidate possible mechanisms underlying this effect. To this end, three experiments were conducted in which the possibility of task repetitions was tied to individual tasks. In Experiment I, the specific repetition proportions varied between participants. The reduction of n - 2 repetition costs was stronger when the relative amount of task repetitions associated with a particular task was high, suggesting that inhibition is reduced when the presence of repetitions tied to a specific task can easily be detected. In Experiment II, task preparation time varied between blocks to investigate whether cue-based preparation underlies this reduction of n - 2 repetition costs. While the duration of the preparation interval had no effect in this respect, additional combined analyses of both experiments revealed an influence of stimulus congruency: n - 2 repetition costs were highest when repetitions were precluded and the task stimulus was incongruent, whereas no effect of stimulus congruence on n - 2 repetition costs was observed with tasks that possibly repeated. This data pattern was replicated in Experiment III. This result is interpreted in terms of task shielding which is reduced for tasks without repetitions, making these tasks more vulnerable to crosstalk from competing tasks when they are still in an inhibited state.

Proactive control of affective distraction: Experience-based but not expectancy-based.

Unpleasant stimuli disrupt ongoing information processing, even when they are entirely task-irrelevant. We examined whether such affective disturbances can be controlled explicitly and proactively. Specifically, we studied two different mechanisms to induce proactive control: the experience of frequent affective distraction and cueing of upcoming affective distraction. We predicted that both mechanisms would shield the attentional system from affective disturbance. Participants solved a letter classification task while being exposed to neutral or negative distractor pictures. We varied whether the proportion of negative distractors was low or high and whether cues for the upcoming type of distractor valence were informative or uninformative. In three experiments (N = 114), we found support for the notion that experience-based control shields information processing from affective disturbances, whereas distractor valence expectations were not helpful. These data suggest that there is no explicit top-down influence on attentional control settings of affective distraction, just adjustments to the context.

Motor imagery entails task-set inhibition.

Motor imagery requires the covert execution of a movement without any overt motor output. Previous studies indicated that motor imagery results in the prolonged inhibition of motor commands. In the present study, we investigated whether motor imagery also leads to the inhibition of more abstract task representations. To do so, we investigated the effect of motor imagery on n - 2 repetition costs, which offer an index of the extent to which task representations are inhibited. Participants switched among three tasks and among two response modes: overt and covert responding (i.e., motor imagery). N - 2 repetition costs were present when the current trial required an overt response but absent when the current trial required a covert response. Furthermore, n - 2 repetition costs were more pronounced when trial n - 1 required a covert response rather than an overt response. This pattern of results suggests that motor imagery also leads to the inhibition of abstract task representations. We discuss our findings in view of current conceptualizations of motor imagery and argue that the inhibitory mechanism entailed by motor imagery targets more than motor commands alone. Finally, we also relate our findings to the mechanisms underlying the inhibition of task representations.

Affective distraction along the flexibility-stability continuum.

This study explored whether conditions that promote flexibility in task processing enhance the detrimental impact of irrelevant negative stimulation on performance. We approached this flexibility from a transient and a sustained perspective, by manipulating whether participants repeated or switched between two tasks in consecutive trials and whether they performed the tasks in separate blocks or randomly mixed. Participants categorised either a letter or the colour of a bar, which were presented close to an irrelevant negative or neutral picture. Performance was worse in the presence of negative rather than neutral pictures. Repeating or switching tasks transiently did not modulate this detrimental impact of affective distraction in three experiments (nExp1 = 32, nExp2 = 32, nExp3 = 64). Attentional capture by negative content did decline in single compared to mixed task contexts, but only when these sustained task contexts also differed in the frequency of affective stimulation. When affective stimulation was the same in mixed and single task contexts, this modulation vanished. Overall, these results suggest that the influence of task-irrelevant negative stimulation on performance is surprisingly independent of cognitive states that favour either flexible or stable processing of task-relevant information.

Effects of global and local task repetition proportion on n - 2 repetition costs.

In task switching research, one of the most straightforward indications for the involvement of inhibitory processes are n - 2 repetition costs. The present study aimed at investigating effects of different types of repetition proportion on n - 2 repetition costs. In Experiments 1 and 2, repetition proportion was varied globally (i.e., equally for all tasks). The occurrence of 33% task repetitions reduced n - 2 repetition costs when varied within as well as between subjects, but no further decline was visible from 33% to 50% task repetitions. This result is interpreted in terms of a shift of balance between task inhibition and task activation due to the occurrence of task repetitions that is independent of the specific repetition proportion. In contrast, when repetition proportion was varied locally (i.e., by differentially manipulating the occurrence of task repetitions for the three tasks involved), n - 2 repetition costs were reduced monotonically from 0% to 50% task repetitions. This result indicates that when the utility inhibition is tied to individual tasks, the cognitive system is able to adjust the deployment of inhibition accordingly, possibly by modulating processes of overcoming inhibition, not releasing it.

Attention to Emotional Information Is Associated With Cytokine Responses to Psychological Stress.

This study aimed to investigate the impact of mental stress on salivary cytokines and attention to emotional stimuli, as well as associations between stress-induced changes of immune and cognitive parameters. In a randomized order a total of 60 young adults were assigned to one of two stress conditions with varying stress intensity. High stress was induced by a socially evaluated Paced Auditory Serial Addition Test (PASAT). As a low stress task a paper-and-pencil version of PASAT was administered. Salivary cytokines were measured before, 5 min after, and 45 min after completion of the stress task, and were assayed for pro- and anti-inflammatory cytokines. Three distinct types of attention - alerting, orienting, and executive control - were measured by the modified Emotional Attention Network Test Integration (E-ANTI). IL-1ß and IL-6 increased only in the high-stress group. Significant increases in IFN-α, IFN-γ, TNF-α, and IL-10 at 45 min after stress induction (all p's < 0.05) were observed in both the high-stress and the low-stress group. Alerting attention was positively related to more pronounced increases in IFN-α and TNF-α in both groups. Further, better orienting attention after presentation of negative cues was associated with higher increases in IFN-α, TNF-α, IL-2, IL-5, and IL-10 in both groups, and higher overall levels of IFN-α, IFN-γ, and IL-12p70 in the high-stress group. There were no systematic gender differences in cytokine responses. We conclude that attention processes modulate the increases of salivary cytokines after stress exposure, and that these effects depend on stress level, particular attention network, and stimulus valence.

Further evidence for functional differences between guessing versus choosing an upcoming task.

We replicated and extended previous evidence regarding functional differences between guessing versus choosing an upcoming task. Participants switched among four tasks and were asked to predict the upcoming task on each trial. These predictions were instructed to participants as either 'guessing' or 'choosing'. Furthermore, we varied the proportion of trials in which the presented task conformed to participants' predictions on three levels. Whereas with choosing instructions unexpectedness affected task switches and repetitions similarly, leaving switch costs unchanged, with guessing instructions switch costs were reduced, that is, task switches were affected less than repetitions. This interaction was unaffected by the proportion of expected tasks. We propose that with choosing, the impact of a mismatch between chosen and presented tasks is reduced by explicit knowledge regarding the proportion of denied choices. With guessing, task unexpectedness mainly increases task difficulty, which is compensated by an increase of cognitive control that reduces switch costs.

Impact of chronic and acute academic stress on lymphocyte subsets and monocyte function.

This study investigated the effects of a temporally confined naturalistic stressor (academic stress) on immune functions. Furthermore, moderating influences of a number of psychological variables were assessed. Five blood samples were obtained from 20 students during an observation period of 8 weeks, starting 4.5 weeks before an exam period up to 1 week following the last exam. The analysis of 45 immune parameters revealed several time-dependent changes attributable to examination stress. We observed a reduction in the absolute numbers of natural killer (NK) cells and monocytes in peripheral blood and a shift towards more immature and naïve cells within NK and T cell populations. In addition, IL-6 and TNF-α production by LPS-stimulated monocytes was increased. Psychological variables were grouped by means of factor analyses into two factors. One factor, which was interpreted as an indication of chronic stress, moderated the relationships between academic stress and percentages of mature CD57+ NK cells. This chronic stress factor was also associated with an increase in memory and a decrease in naïve CD8 T cells and increased serum levels of IL-17. The present study identifies important potential psychological mediators of stress-induced changes in specific immunological parameters.

Integration of Advance Information about a Forthcoming Task Switch - Evidence from Eye Blink Rates.

We investigated task switching among four tasks by means of a modified cuing procedure with two types of cues. One type of cue consisted of a standard task cue indicating the next task. In half of the trials, this task cue was preceded by another type of cue that reduced the set of candidate tasks from four to two tasks. In addition, we measured participants' spontaneous eye blink rates (EBRs) at the beginning, in the middle, and at the end of the experiment. Whereas interindividual differences in mean EBR had no pronounced effect on task switching performance, changes in EBRs during the first half of the experiment significantly modulated the interaction of the effects of the two types of cues. We suggest that changes in EBRs in the early phase of the experiment reflect adaptations of dopaminergic projections serving to integrate advance information about a forthcoming task switch.

Measuring the immune system: a comprehensive approach for the analysis of immune functions in humans.

The immune system is essential to provide protection from infections and cancer. Disturbances in immune function can therefore directly affect the health of the affected individual. Many extrinsic and intrinsic factors such as exposure to chemicals, stress, nutrition and age have been reported to influence the immune system. These influences can affect various components of the immune system, and we are just beginning to understand the causalities of these changes. To investigate such disturbances, it is therefore essential to analyze the different components of the immune system in a comprehensive fashion. Here, we demonstrate such an approach which provides information about total number of leukocytes, detailed quantitative and qualitative changes in the composition of lymphocyte subsets, cytokine levels in serum and functional properties of T cells, NK cells and monocytes. Using samples from a cohort of 24 healthy volunteers, we demonstrate the feasibility of our approach to detect changes in immune functions.

Guessing versus Choosing an Upcoming Task.

We compared the effects of guessing vs. choosing an upcoming task. In a task-switching paradigm with four tasks, two groups of participants were asked to either guess or choose which task will be presented next under otherwise identical conditions. The upcoming task corresponded to participants' guesses or choices in 75 % of the trials. However, only participants in the Choosing condition were correctly informed about this, whereas participants in the Guessing condition were told that tasks were determined at random. In the Guessing condition, we replicated previous findings of a pronounced reduction of switch costs in case of incorrect guesses. This switch cost reduction was considerably less pronounced with denied choices in the Choosing condition. We suggest that in the Choosing condition, the signaling of prediction errors associated with denied choices is attenuated because a certain proportion of denied choices is consistent with the overall representation of the situation as conveyed by task instructions. In the Guessing condition, in contrast, the mismatch of guessed and actual task is resolved solely on the level of individual trials by strengthening the representation of the actual task.