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The paper discusses a task preference-based bottleneck assignment problem in which there are n tasks that are divided into three phases in order of preference of performance of various tasks. The assignment problem is balanced with an equal number of agents and tasks. An agent can perform only one task and each task can be accomplished by exactly one agent. Tasks belonging to a particular phase cannot be commenced until the tasks of the previous phase have been completed. Given the performance time of each task by each agent, the aim is to find an assignment of agents to the tasks that minimize the total completion time of all tasks. The total completion time here refers to the sum of the overall completion times of three phases. An iterative algorithm for solving such a task preference-based bottleneck assignment problem is proposed in the paper. The proposed algorithm is validated with the help of theoretical results and numerical illustration. The algorithm has been coded in MATLAB and the computational results show that the algorithm performs well in terms of computing time for finding optimal assignments for task preference-based assignment problems of different sizes. [ABSTRACT FROM AUTHOR]

For complex dynamic interactive tasks (such as aviating), operators need to continuously extract information from areas of interest (AOIs) through eye movement to maintain high level of situation awareness (SA), as failures of SA may cause task performance degradation, even system accident. Most of the current eye movement models focus on either static tasks (such as image viewing) or simple dynamic tasks (such as video watching), without considering SA. In this study, an eye movement model with the goal of maximizing SA is proposed based on Markov decision process (MDP), which is designed to describe the dynamic eye movement of experienced operators in dynamic interactive tasks. Two top-down factors, expectancy and value, are introduced into this model to represent the update probability and the importance of information in AOIs, respectively. In particular, the model regards sequence of eye fixations to different AOIs as sequential decisions to maximize the SA-related reward (value) in the context of uncertain information update (expectancy). Further, this model was validated with a flight simulation experiment. Results show that the predicted probabilities of fixation on and shift between AOIs are highly correlated ( R = 0.928 and R = 0.951 , respectively) with those of the experiment data. [ABSTRACT FROM AUTHOR]

Metacognition is often considered a critical component of learning and higher-order cognition; however, does metacognitive accuracy remain constant across all tasks, specifically in tasks that involve physical or procedural components? To investigate the consistency of metacognitive judgments across various task types, participants completed word and number recall tasks, and also completed three simple physical skill tasks (e.g., catching a ball in a cup). Participants made metacognitive judgments about their performance in all tasks. Results indicated that while participants demonstrated traditional levels of relative metacognitive accuracy in more cognitive tasks, participants were significantly more accurate in their judgments for physical skill tasks. In other words, relative accuracy for metacognitive judgments in physical tasks appears to be significantly higher than for cognitive tasks. This represents the first such demonstration of this effect and suggests that characteristics of physical tasks somehow improve participants' judgments of how well they have learned. [ABSTRACT FROM AUTHOR]

The working memory Stroop task is to name the color of a rectangular patch with keypress while holding a color word in working memory. Previous studies using this variant of the Stroop task have shown that congruency between the color patch and the color word significantly affects both color naming and working memory, with the worsening of task performance when the color patch is semantically incongruent rather than congruent with the color word. However, it remains unclear with regard to cognitive mechanisms underlying such congruency effects in the working memory Stroop task. By including a control condition among the congruent and incongruent conditions in a working memory Stroop task, the present study showed that nearly all of the working memory Stroop effect can be facilitation, and that interference, if present, is markedly smaller than facilitation in this form of the Stroop effect. There was also a critical contrast between the working memory and classic Stroop effects in terms of facilitation and interference, with larger facilitation and smaller interference in the working memory Stroop effect than in the classic Stroop effect. Moreover, working memory for a color word can be either facilitated or interfered with by the perceptual judgment (color naming) of an interposed color patch during the retention interval, depending on whether the color patch is semantically congruent or incongruent with the color word. Together, these results suggest that both facilitation and interference mechanisms can contribute to the overall congruency effects in the working memory Stroop task. [ABSTRACT FROM AUTHOR]

The literature suggests that deaf individuals lag behind their hearing peers in terms of mathematical abilities. However, it is still unknown how unique sensorimotor experiences, like deafness, might shape number-space interactions. We still do not know either the spatial frame of reference deaf individuals use to map numbers onto space in different numerical tasks. To examine these issues, deaf, hearing signer and hearing control adults were asked to perform a number comparison and a parity judgment task with the hands uncrossed and crossed over the body midline. Deafness appears to selectively affect the performance of the numerical task relying on verbal processes while keeping intact the task relying on visuospatial processes. Indeed, while a classic SNARC effect was found in all groups and in both hand postures of the number comparison task, deaf adults did not show the SNARC effect in both hand postures of the parity judgment task. These results are discussed in light of the spatial component characterizing the counting system used in sign language. [ABSTRACT FROM AUTHOR]

Extractive foraging tasks, such as digging, are broadly practiced among hunter-gatherer populations in different ecological conditions. Despite tuber-gathering tasks being widely practiced by children and adolescents, little research has focused on the physical traits associated with digging ability. Here, we assess how age and energetic expenditure affect the performance of this extractive task. Using an experimental approach, the energetic cost of digging to extract simulated tubers is evaluated in a sample of 40 urban children and adolescents of both sexes to measure the intensity of the physical effort and the influence of several anatomical variables. Digging is a moderately vigorous activity for inexperienced girls and boys from 8 to 14 years old, and it requires significant physical effort depending on strength and body size. However, extracting subterranean resources is a task that may be performed effectively without previous training. Sex-specific and age-specific differences in the net energy expenditure of digging were detected, even though both sexes exhibited similar proficiency levels when performing the task. Our results highlight that both boys and girls spend considerable energy while digging, with differences largely driven by body size and age. Other factors beyond ability and experience, such as strength and body size, may influence the proficiency of juveniles in performing certain physically intensive foraging tasks, such as gathering tubers. [ABSTRACT FROM AUTHOR]

The cognitive processes underlying the ability of human performers to trade speed for accuracy is often conceptualized within evidence accumulation models, but it is not yet clear whether and how these models can account for decision-making in the presence of various sources of conflicting information. In the present study, we provide evidence that speed-accuracy tradeoffs (SATs) can have opposing effects on performance across two different conflict tasks. Specifically, in a single preregistered experiment, the mean reaction time (RT) congruency effect in the Simon task increased, whereas the mean RT congruency effect in the Eriksen task decreased, when the focus was put on response speed versus accuracy. Critically, distributional RT analyses revealed distinct delta plot patterns across tasks, thus indicating that the unfolding of distractor-based response activation in time is sufficient to explain the opposing pattern of congruency effects. In addition, a recent evidence accumulation model with the notion of time-varying conflicting information was successfully fitted to the experimental data. These fits revealed task-specific time-courses of distractor-based activation and suggested that time pressure substantially decreases decision boundaries in addition to reducing the duration of non-decision processes and the rate of evidence accumulation. Overall, the present results suggest that time pressure can have multiple effects in decision-making under conflict, but that strategic adjustments of decision boundaries in conjunction with different time-courses of distractor-based activation can produce counteracting effects on task performance with different types of distracting sources of information. [ABSTRACT FROM AUTHOR]

Individuals who contract Covid-19 often experience problems with memory, attention, and concentration, even after recovering from the initial illness. In the current manuscript, we argue that these symptoms are likely to manifest as cognitive failures in the workplace. Downstream, cognitive failures were expected to be associated with decreased task performance and increased turnover intentions. We collected data from a sample of working adults who either had (n = 45) or had not (n = 49) contracted Covid-19 at least one month prior to the study. Both groups were matched on key demographic characteristics. As anticipated, individuals who had contracted Covid-19 reported significantly more cognitive failures at work, relative to individuals who did not. More so, having contracted Covid-19 had significant indirect effects on task performance and turnover intentions via cognitive failure. These results indicate that beyond physical harm, Covid-19 can also have a detrimental influence on an individual's capacity to perform at work. [ABSTRACT FROM AUTHOR]

Recent research suggests that fear and avoidance responding based on derived transformation of functions may be considered functionally independent. The current study examined the impact of a fear-related verbal-rehearsal task on performance on two implicit relational assessment procedures (IRAPs), actual approach behavior towards a live spider (a BAT), and the relationship between the IRAPs and the BAT. The study was conducted over 3 separate days. Day 1 involved exposure to a series of questionnaires, the fear-related verbal-rehearsal task and homework. Day 2 involved a second exposure to the fear-related verbal-rehearsal task and exposure to the IRAPs and BAT. The final day involved a second exposure to the IRAPs and BAT. Participants were randomly assigned to one of three conditions (i.e., control, accept, or reduce fear). Broadly similar findings were obtained for performance on the IRAPs as were reported by Leech et al. (2017). No significant differences between the conditions emerged on the self-report measures, IRAPs, or the BAT. However, correlations between performances on the IRAPs and the BAT were concentrated almost exclusively in the control and reduce-fear conditions rather than the accept-fear condition. The replication of results reported here provide further evidence of the functional independence of approach and avoidance responding. Furthermore, the differential pattern of correlations observed provide further evidence that the fear-related verbal-rehearsal task affected a behavior–behavior relation, which may be directly relevant to the concept of defusion in the ACT literature. In addition, the differential arbitrarily applicable relational responding effects (DAARRE) model offers an alternative explanation for the results reported. [ABSTRACT FROM AUTHOR]

The central cloud facilities based on virtual machines offer many benefits to reduce the scheduling costs and improve service availability and accessibility. The approach of cloud computing is practical due to the combination of security features and online services. In the tasks transfer, the source and target domains have differing feature spaces. This challenge becomes more complicated in network traffic, which leads to data transfer delay, and some critical tasks could not deliver at the right time. This paper proposes an efficient optimization method for task scheduling based on a hybrid multi-verse optimizer with a genetic algorithm called MVO-GA. The proposed MVO-GA is proposed to enhance the performance of tasks transfer via the cloud network based on cloud resources' workload. It is necessary to provide adequate transfer decisions to reschedule the transfer tasks based on the gathered tasks' efficiency weight in the cloud. The proposed method (MVO-GA) works on multiple properties of cloud resources: speed, capacity, task size, number of tasks, number of virtual machines, and throughput. The proposed method successfully optimizes the task scheduling of a large number of tasks (i.e., 1000–2000). The proposed MVO-GA got promising results in optimizing the large cloud tasks' transfer time, which reflects its effectiveness. The proposed method is evaluated based on using the simulation environment of the cloud using MATLAB distrusted system. [ABSTRACT FROM AUTHOR]

This paper presents a human-robot interaction (HRI) study of a dedicated Mission Specialist interface for performing telemanipulation tasks using a small unoccupied aerial vehicle (UAV). Current literature suggests that the successful completion of aerial manipulation tasks in real-world environments requires human input due to challenges in autonomous perception and control. Visual information of the remote environment in a telemanipulation interface can significantly affect performance under direct control; however, the effects of interface visualizations on task performance have not been studied for UAV telemanipulation. This work evaluated the effects of interface viewpoint on aerial manipulation task performance. The interfaces evaluated in this study included video streams from cameras located onboard the UAV, including: (i) a manipulator egocentric view, (ii) a manipulator exocentric view, and (iii) a combination of egocentric and exocentric views. A total of 36 participants completed three different manipulation tasks using all three interface conditions. The observations and results showed that both the exocentric and mixed view configurations contributed to improved task performance over an egocentric-only interface. Further, this study resulted in data regarding view use, view effectiveness, and task type that can be used for further developing interfacing for aerial manipulators that change and adapt to the environment and task. [ABSTRACT FROM AUTHOR]

Many areas of psychology assume that performance on tasks of interest is stable through time. Here, using time-sensitive modeling of working memory task performance, we show not only was this assumption incorrect, but that certain components of the performance trajectory (e.g., final task performance; rate of change) were independently predictive of fluid intelligence. This fact has clear implications for theoretical frameworks linking working memory and fluid intelligence, and beyond. [ABSTRACT FROM AUTHOR]

How do we compare the difficulty of different kinds of tasks, and how we do sequence tasks of different kinds when the basis for the ordering is the tasks' difficulty levels? The ability to do these things requires a common currency, but the identity of that currency, if it exists, is unknown. We hypothesized that people may believe that the time that attention is paid to tasks enables people to compare and sequence tasks of different kinds. To evaluate this hypothesis, we tested three groups of participants. One group estimated the proportion of time that performance of a task requires attention—what we called attention time proportions or ATPs. We obtained ATPs for tasks that were "more intellectual" (counting) and others that were "more physical" (locomotion). Two additional groups made 2-alternative-forced-choice decisions about the relative ease and preferred sequencing of all possible pairs of tasks for which ATPs were independently obtained. We found that ATPs predicted judgments of task difficulty and preferred task order. [ABSTRACT FROM AUTHOR]

Studies on the effects of dual tasking in patients with chronic inflammatory rheumatic diseases are limited. The aim of this study was to assess dual tasking while walking in patients with axial spondyloarthritis (axSpA) in comparison to healthy controls. Thirty patients with axSpA and thirty healthy controls underwent a 10-m walk test at a self-selected comfortable walking speed in single- and dual-task conditions. Foot-worn inertial sensors were used to compute spatiotemporal gait parameters. Analysis of spatiotemporal gait parameters showed that the secondary manual task negatively affected walking performance in terms of significantly decreased mean speed (p < 0.001), stride length (p < 0.001) and swing time (p = 0.008) and increased double support (p = 0.002) and stance time (p = 0.008). No significant interaction of group and condition was observed. Both groups showed lower gait performance in dual task condition by reducing speed, swing time and stride length, and increasing double support and stance time. Patients with axSpA were not more affected by the dual task than matched healthy controls, suggesting that the secondary manual task did not require greater attention in patients with axSpA. Increasing the complexity of the walking and/or secondary task may increase the sensitivity of the dual-task design to axial spondyloarthritis. [ABSTRACT FROM AUTHOR]

The information and communication technology (ICT) sector within the Netherlands is a major driver of globalization, the country's economic growth and innovation. The Dutch ICT sector's performance is increasingly becoming dependent upon employee driven innovations in order to address the needs of the sectors they service. In other words, the ICT sector within the Netherlands is largely dependent upon the performance and innovative capacity of its employees; both of which are functions of employee engagement. Given the high demand, and low supply of talent within this sector, ICT organizations need to develop innovative ways to enhance the performance capacities of its people. Developing an engaged and highly innovative workforce seems to be an efficient way to activate employees' performance. As such, the aim of this paper was to investigate the mediating function of employee driven innovative work behaviors in the relationship between work engagement and task performance within the a Dutch ICT consulting firm. A cross-sectional survey-based research design, employing a census-based sampling method, was employed to obtain data from a global ICT consulting firm within the Netherlands (n = 232). The Utrecht Work Engagement Scale, the Innovative Work Behavior Scale and the Task Performance Scale was used to assess the associative subjective experiences of ICT employees. The results showed that work engagement is a significant driver for innovative work behaviors, which in turn affects the task performance of employees. Further, innovative work behaviors are therefore important to translate the engaging energies of employees into performance. This paper discusses the theoretical and practical implications of these findings. [ABSTRACT FROM AUTHOR]

Previous work investigating the effect of rTMS of left Dorso-Lateral Prefrontal Cortex (DLPFC) on Stroop task performance reports no changes to the Stroop effect but reduced reaction times on both congruent and incongruent trials relative to sham stimulation; an effect attributed to an enhanced attentional (or task) set for colour classification. The present study tested this account by investigating whether, relative to vertex stimulation, rTMS of the left DLPFC modifies task conflict, a form of conflict that arises when task sets for colour classification and word reading compete, given that this particular type of conflict would be reduced by an enhanced task set for colour classification. Furthermore, the present study included measures of other forms of conflict present in the Stroop task (response and semantic conflict), the potential effects on which would have been hidden in previous studies employing only incongruent and congruent stimuli. Our data showed that left DLPFC stimulation had no effect on the magnitude of task conflict, nor did it affect response, semantic or overall conflict (where the null is supported by sensitive Bayes Factors in most cases). However, consistent with previous research left DLPFC stimulation had the general effect of reducing reaction times. We, therefore, show for the first time that relative to real vertex stimulation left DLPFC stimulation does not modify Stroop interference. Alternative accounts of the role of the left DLPFC in Stroop task performance in which it either modifies response thresholds or facilitates responding by keeping the correct response keys active in working memory are discussed. [ABSTRACT FROM AUTHOR]

Motor adaptation plays an important role in the acquisition of new motor skills. It has been reported that cognitive tasks can promote motor adaptation; however, which cognitive tasks effectively promote motor adaptation remains unknown. This study aimed to examine what factors of cognitive tasks contribute to promoting motor adaptation. Forty-two healthy young adults were randomly assigned to one of three groups: incongruent Stroop task group (iSTG), congruent Stroop task group (cSTG), and control group (CG). All participants underwent 20 blocks of a mouse-tracking task on the 1st and 2nd days. Before the mouse tracking task on the 1st day, the iSTG and cSTG completed the incongruent and congruent Stroop tasks, respectively. Participants in the CG did not perform any cognitive tasks. On the 28th day, all participants underwent 3 blocks of the mouse tracking task to evaluate their retention of motor adaptation. As a result, on the 1st day, the mouse tracking task performance improved equally for both groups. However, on the 2nd and 28th days, the mouse tracking task performance in the iSTG showed greater improvements for all blocks compared to those in the CG. These results suggest that the incongruent Stroop task promotes motor adaptation, but the congruent Stroop task does not. In addition, it is suggested that factors, which are primarily involved in the incongruent Stroop task, might promote motor adaptation. [ABSTRACT FROM AUTHOR]

Task performance improves when the required tasks are predicted by the preceding time intervals, suggesting that participants form time-based task expectancies. In the present study, we pursued the question whether temporal predictability of tasks can also influence task choice. For this purpose, we conducted three experiments using a hybrid task-switching paradigm (with two tasks) combining forced-choice and free-choice trials. Each trial was preceded by either a short (500 ms) or a long (1500 ms) foreperiod. In forced-choice trials, the instructed task was predicted by the length of the foreperiod (Exp. 1A and 1B: 100% foreperiod-task contingencies; Exp. 2: 80% foreperiod-task contingencies). In the remaining trials, participants were free to choose which task to perform. In all three experiments, we found that participants' task choice was influenced by the foreperiod-task contingencies implemented in forced-choice trials. Specifically, participants were overall biased to choose tasks compatible with these contingencies; these compatible choice rates were larger for the short compared to the long foreperiod. Our findings suggest that learned time-based task expectancies influence subjects' voluntary task choice and that an initially present task bias toward the "short" task is not always overcome at the long foreperiod. We discuss potential underlying mechanisms against the background of voluntary task switching and interval timing. [ABSTRACT FROM AUTHOR]

Behaviour occurs not as isolated incidents, but within an ongoing sequence of events. The task-switching paradigm provides a useful way to investigate the impact of different events upon subsequent performance. An implication of two-stage task-switching models is that preparing a task without performing it might affect task readiness only to a limited extent. However, recent research has surprisingly shown larger switch costs following preparation ("cue-only" trials) than following performance ("completed" trials). We set out to conduct a rigorous comparison of the size of switch costs following cue-only versus completed trials. In Experiments 1 and 2, we controlled the timing between critical trial events. This had the effect of roughly equating, but not reversing, the relative size of switch costs. In Experiment 3, we restructured the paradigm to equate the predictability of cue and target events. Switch costs following cue-only trials were now smaller than those following completed trials. These studies confirm that task preparation alone is sufficient to drive subsequent switch costs. They also indicate that task performance might increase the size of these costs, consistent with two-stage task-switching models. Switch costs appear to be affected by both the timing and predictability of trial events. [ABSTRACT FROM AUTHOR]

The strength model of self-control proposes that all acts of self-control are energized by one global limited resource that becomes temporarily depleted by a primary self-control task, leading to impaired self-control performance in secondary self-control tasks. However, failed replications have cast doubt on the existence of this so-called ego depletion effect. Here, we investigated between-task (i.e., variation in self-control tasks) and within-task variation (i.e., task duration) as possible explanations for the conflicting literature on ego depletion effects. In a high-powered experiment (N = 709 participants), we used two established self-control tasks (Stroop task, transcription task) to test how variations in the duration of primary and secondary self-control tasks (2, 4, 8, or 16 min per task) affect the occurrence of an ego depletion effect (i.e., impaired performance in the secondary task). In line with the ego depletion hypothesis, subjects perceived longer lasting secondary tasks as more self-control demanding. Contrary to the ego depletion hypothesis, however, performance did neither suffer from prior self-control exertion, nor as a function of task duration. If anything, performance tended to improve when the primary self-control task lasted longer. These effects did not differ between the two self-control tasks, suggesting that the observed null findings were independent of task type. [ABSTRACT FROM AUTHOR]

Gait stability and secondary task performance are affected by the need to share attention when dual-tasking. Further decrements may result from the need to switch attention between multiple secondary tasks. The aim of the current study was to determine the effects of attention switching upon gait stability and task performance in healthy younger and older adults. Ten healthy younger and ten healthy older adults walked on a treadmill at their preferred speed during three trials including: (1) baseline walking; (2) non-switching task walking, requiring response to an auditory-spatial or visual-spatial cue presented in an expected order; and (3) switching task walking, which required response to an auditory-spatial or visual-spatial cue presented in an unexpected order. Response time and accuracy, the margin of stability in the frontal (MoSML) and sagittal planes (MoSA: anterior, MoSP: posterior), step width and step length were calculated for non-switching and switching tasks. The MoSML, MoSA, MoSP, step width and step length during non-switching and switching tasks were normalized to baseline walking. Older adults took significantly longer to respond to cues and made more errors during the switching task compared to younger adults. Younger adults took narrower steps (p < 0.01) and displayed a reduction in MoSML (p < 0.01) during the switching task compared with the non-switching task. Conversely, older adults displayed no differences in MoSML between tasks. These findings suggest that attention switching results in different task prioritization strategies in younger and older adults during walking. [ABSTRACT FROM AUTHOR]

When processing of two tasks overlaps, performance is known to suffer. In the well-established psychological refractory period (PRP) paradigm, tasks are triggered by two stimuli with a short temporal delay (stimulus onset asynchrony; SOA), thereby allowing control of the degree of task overlap. A decrease of the SOA reliably yields longer RTs of the task associated with the second stimulus (Task 2) while performance in the other task (Task 1) remains largely unaffected. This Task 2-specific SOA effect is usually interpreted in terms of central capacity limitations. Particularly, it has been assumed that response selection in Task 2 is delayed due to the allocation of less capacity until this process has been completed in Task 1. Recently, another important factor determining task prioritization has been proposed—namely, the particular effector systems associated with tasks. Here, we study both sources of task prioritization simultaneously by systematically combining three different effector systems (pairwise combinations of oculomotor, vocal, and manual responses) in the PRP paradigm. Specifically, we asked whether task order-based task prioritization (SOA effect) is modulated as a function of Task 2 effector system. The results indicate a modulation of SOA effects when the same (oculomotor) Task 1 is combined with a vocal versus a manual Task 2. This is incompatible with the assumption that SOA effects are solely determined by Task 1 response selection duration. Instead, they support the view that dual-task processing bottlenecks are resolved by establishing a capacity allocation scheme fed by multiple input factors, including attentional weights associated with particular effector systems. [ABSTRACT FROM AUTHOR]

The proximity of hand position alters the processing of visual stimuli. Stimuli presented close (proximal) to hands receive an enhanced allocation of visual attention compared to stimuli presented far (distal) from hands. In the present dual-task study we studied the consequences of this preferential processing when the stimulus for Task 1 (S1) and the stimulus for Task 2 (S2) were presented together and were assigned to specific response hands (R1 and R2) located proximal (at the monitor) versus distal (in the lap) to the stimuli. In two experiments, we tested whether stimulus–hand proximity affected the extent of between-task interference (i.e., influence of additional Task 2 processing on primary Task 1 processing). In Experiment 1, results showed that stimulus–hand proximity reduced the amount of between-task interference compared to the distal stimulus–hand condition. Extending these findings, in Experiment 2 a further reduction of between-task interference was obtained when a single hand was located at the monitor instead of two hands. These results are inconsistent with the assumption of a generally increased attentional processing benefit for multiple stimuli within hand space. Instead, these findings speak for a hand-specific processing benefit that supports more separate processing of two tasks. Together these findings demonstrate that stimulus–hand proximity affects the quality of multiple task performance, which is discussed in the context of both, basic and applied cognitive research. [ABSTRACT FROM AUTHOR]

Does cognitive control operate globally (across task sets) or locally (within a task set)? Recently, two of the current co-authors (Hazeltine and Schumacher 2016; Schumacher and Hazeltine 2016) proposed that humans represent tasks as task files: hierarchically structured, compartmentalized subsets of our current goals and motivations, task instructions, and relevant stimuli and responses that are selected during task performance according to associated contextual rules. Here, we hypothesize that these task representations bound the implementation of cognitive control at distinct levels of this hierarchical structure. To investigate how task structure influences the implementation of control processes, we conducted a pair of experiments that utilized a precuing procedure. To manipulate task structure, we gave participants mappings in which two stimulus sets were either mapped so that each set was separated by response hand or both sets were interleaved across hands. In Experiment 1, participants responded to sets of images distinguished by their semantic category; in Experiment 2, they responded to sets based on different perceptual features (viz., location or color). During each experiment, precues could give information about the stimulus category or response hand for the upcoming target. The results indicate that participants with separated mappings represented the task hierarchically, while those with interleaved mappings did not. This pattern was consistent across experiments, despite the differences in the way that each set of stimuli influenced representation of the low-level task features. These findings suggest that task structure can be represented hierarchically, and that this structure supports distinct cognitive control processes at different hierarchical levels. [ABSTRACT FROM AUTHOR]

Eyeblink conditioning, finger tapping, and prism adaptation are three tasks that have been linked to the cerebellum. Previous research suggests that these tasks recruit distinct but partially overlapping parts of the cerebellum, as well as different extra-cerebellar networks. However, the relationships between the performances on these tasks remain unclear. Here we tested eyeblink conditioning, finger tapping, and prism adaptation in 42 children and 44 adults and estimated the degree of correlation between the performance measures. The results show that performance on all three tasks improves with age in typically developing school-aged children. However, the correlations between the performance measures of the different tasks were consistently weak and without any consistent directions. This reinforces the view that eyeblink conditioning, finger tapping, and prism adaptation rely on distinct mechanisms. Consequently, performance on these tasks cannot be used separately to assess a common cerebellar function or to make general conclusions about cerebellar dysfunction. However, together, these three behavioral tasks have the potential to contribute to a nuanced picture of human cerebellar functions during development. [ABSTRACT FROM AUTHOR]

In seven experiments we examined haptic memory for location, item information, and orientation for 12 tangible pictures, geometrical forms, and letter shapes in the change task. The study evaluated the influence of stimulus familiarity on change task performance. In the change task, participants are exposed to an array of patterns and subsequently have to indicate which ones have been altered on a second array. We also sought to determine whether prior demonstrations of female advantages in the haptic change task were reliable (Heller et al., 2010). The present experiments failed to replicate gender differences, overall with large samples. When participants were told about the nature of the picture change they should anticipate (45° or 90° rotation, location exchange), comparable performance was found for the groups in Experiment 1. In another experiment, participants were not told what sort of change might occur, and higher performance was found for the 90° rotation group than for the location exchange and 45° groups. Participants benefited from explicit instructions about the nature of the change. Telling participants the names of the raised-line pictures during initial study improved both change performance with the pictures and subsequent recognition. Changes derived from the substitution of new tangible print capital letters were easier to detect than location exchanges of the letters. Changes from letters to geometrical shapes were easy to detect. High performance resulted when participants were told to indicate which tangible letters were turned (45° or 90°) or exchanged in a final experiment. The results suggest the importance of pattern familiarity in haptic spatial memory. [ABSTRACT FROM AUTHOR]

We study the dynamic task assignment problem in which multiple dispersed vehicles are employed to visit a set of targets. Some targets' locations are initially known and the others are dynamically randomly generated during a finite time horizon. The objective is to visit all the target locations while trying to minimize the vehicles' total travel time. Based on existing algorithms used to deal with static multi-vehicle task assignment, two types of dynamic task assignments, namely event-triggered and time-triggered, are studied to investigate what the appropriate time instants should be to change in real time the assignment of the target locations in response to the newly generated target locations. Furthermore, for both the event- and time-triggered assignments, we propose several algorithms to investigate how to distribute the newly generated target locations to the vehicles. Extensive numerical simulations are carried out which show better performance of the event-triggered task assignment algorithms over the time-triggered algorithms under different arrival rates of the newly generated target locations. [ABSTRACT FROM AUTHOR]

There is growing evidence suggesting that positive affect promotes cognitive flexibility at the cost of increased distractibility and decreased proactive control. Regarding the latter effect, some studies revealed inconsistent or even diverging findings casting doubt on the reliability of this observation. Recently, it has been shown that motivation can counteract positive affect effects. Here, the authors provide evidence for another factor that opposes positive affect effects, namely time on and experience with a task. To this end, the well proven AX-continuous performance task (AX-CPT) was used. Three groups of participants received three blocks of the AX-CPT with a positive affect manipulation (positive group) or neutral affect manipulation (neutral group) or alternating affect blocks (mixed group: pos-neut-pos). Results confirmed the positive affect effect associated with decreased proactive control in the positive and mixed group as compared to the neutral group. Most importantly, all groups showed an increase in proactive control with increasing time on task supporting our prediction that time on task is another factor opposing the positive affect effect. The results thus reveal the sensitivity of the positive affect effect to strategic influences developed with increasing experience with the given task. Implications for future research on the interplay of mild positive affect and cognitive control will be discussed. [ABSTRACT FROM AUTHOR]

Tasks that require the cooperation of both hands and arms are common in human everyday life. Coordination helps to synchronize in space and temporally motion of the upper limbs. In fine bimanual tasks, coordination enables also to achieve higher degrees of precision that could be obtained from a single hand. We studied the acquisition of bimanual fine manipulation skills in watchmaking tasks, which require assembly of pieces at millimeter scale. It demands years of training. We contrasted motion kinematics performed by novice apprentices to those of professionals. Fifteen subjects, ten novices and five experts, participated in the study. We recorded force applied on the watch face and kinematics of fingers and arms. Results indicate that expert subjects wisely place their fingers on the tools to achieve higher dexterity. Compared to novices, experts also tend to align task-demanded force application with the optimal force transmission direction of the dominant arm. To understand the cognitive processes underpinning the different coordination patterns across experts and novice subjects, we followed the optimal control theoretical framework and hypothesize that the difference in task performances is caused by changes in the central nervous system's optimal criteria. We formulated kinematic metrics to evaluate the coordination patterns and exploit inverse optimization approach to infer the optimal criteria. We interpret the human acquisition of novel coordination patterns as an alteration in the composition structure of the central nervous system's optimal criteria accompanied by the learning process. [ABSTRACT FROM AUTHOR]

The ecological approach to comparative cognition emphasizes that the ecological and social environment are important predictors of cognitive performance. We used this approach to test whether differences in habitat use and social behavior in the facultative Caribbean cleaning goby Elacatinus prochilos predict differences in learning performance in two discriminatory two-choice tasks. This species has two behavioral ecotypes: one that frequently engages in cleaning interactions and inhabits corals in male–female pairs (cleaning gobies) and another that rarely engages in cleaning interactions and inhabits barrel sponges in large groups (sponge-dwellers). We predicted that cleaning gobies would outperform sponge-dwellers in a pattern-cued task, which consisted of identifying the pattern on a plate that consistently provided food, while sponge-dwellers would outperform cleaning gobies in a spatial task, which consisted of identifying the location of the plate. Contrary to our predictions, there was no difference in performance between the two ecotypes. Most of the gobies performed poorly in the pattern-cued task and well in the spatial task. A possible explanation for these results is that the association of a pattern with positive and negative reinforcement may not be a pre-requisite for engaging in cleaning interactions, while spatial skills might be equally required in both ecotypes. Alternatively, the two ecotypes can flexibly adjust to new feeding conditions, which would explain their similar performance in the spatial task. Further research should investigate which aspects of E. prochilos' social and ecological environment might impose challenges that require spatial cognition and whether individuals can flexibly adjust to new habitats and feeding conditions. [ABSTRACT FROM AUTHOR]

This investigation examined whether previous findings in preferential selection using laboratory simulations, which have used leadership tasks and perceived performance, generalize to cognitively oriented tasks and actual performance. We tested competing perspectives derived from two theoretical accounts of stereotype threat theory: regulatory focus and executive control interference. Non-stigmatized (Whites and Asians) and stigmatized (Hispanics and Blacks; total n = 513) individuals first took a cognitive ability test to be selected for a subsequent task and a chance to win a cash prize. They were then randomly assigned to an explanation concerning selection for a proofreading task based on merit, gender, or race. Results tended to support the regulatory focus view. The main study showed there were no significant differences in performance quantity or quality among participants who were selected based on merit or gender. Among those selected on race, stigmatized participants had lower performance quantity but higher performance quality (i.e., they were slower but more accurate) than non-stigmatized participants. A follow-up study (n = 252) found that stigmatized people selected based on race had more prevention concerns than non-stigmatized people. We discuss previous findings in preferential selection research utilizing experiments and conclude that the regulatory focus perspective can account for these results. Our research also shows that by using different outcomes, it is possible to qualify the allegedly harmful effects of preferential selection. This study is the first to experimentally examine the effects of preferential selection on actual task performance in cognitively oriented tasks. [ABSTRACT FROM AUTHOR]

During voluntary task selection, a number of internal and external biases may guide such a choice. However, it is not well understood how reward influences task selection when multiple options are possible. To address this issue, we examined brain activation in a voluntary task-switching paradigm while participants underwent fMRI (n = 19). To reinforce the overall goal to choose the tasks randomly, participants were told of a large bonus that they would receive at the end of the experiment for making random task choices. We also examined how occasional, random rewards influenced both task performance and brain activation. We hypothesized that these transient rewards would increase the value of the just-performed task, and therefore bias participants to choose to repeat the same task on the subsequent trial. Contrary to expectations, transient reward had no consistent behavioral effect on subsequent task choice. Nevertheless, the receipt of such rewards did influence activation in brain regions associated with reward processing as well as those associated with goal-directed control. In addition, reward on a prior trial was found to influence activation during task choice on a subsequent trial, with greater activation in a number of executive function regions compared with no-reward trials. We posit that both the random presentation of transient rewards and the overall task bonus for random task choices together reinforced the goal to choose the tasks randomly, which in turn influenced activation in both reward-related regions and those regions involved in abstract goal processing. [ABSTRACT FROM AUTHOR]

Self-rated mental effort has been and continues to be the most widely used measure of cognitive load. This single-item measure is often used as a predictor variable in linear models for predicting performance or some other response variable. While an advantage of linear models is that they are fairly easy to understand, they fall short when the relations between variables of interest are clearly non-linear. The current study focused on a reanalysis of data of four recently published studies in which self-rated mental effort was measured repeatedly along with either workload, time on task—viewing time in one study, response time in another study—or self-rated certainty of correct task performance. A core outcome of the reanalysis is a preference towards mental effort as a non-linear instead of linear predictor in three of the four studies: quadratic (workload), quadratic (response time), and cubic (certainty); only in the case of viewing time, mental effort as a linear predictor was found to be the preferred solution. Implications of this finding for the interpretation of self-rated mental effort, indicators of cognitive load involving time on task, and metacognition-related response variables such as self-rated certainty are discussed. [ABSTRACT FROM AUTHOR]

The presence of motor redundancy means that movement variability can be split into a 'task-space' component that affects task performance, and a 'null space' component which has no effect on task performance. While the control of task-space variability during learning is essential, because it is directly linked to performance, how the nervous system controls null space variability during learning has not been well understood. One factor that has been hypothesized to govern the change in null space variability with learning is task difficulty, but this has not been directly tested. Here, we examined how task difficulty influences the change in null space variability with learning. Healthy, college-aged participants (N = 36) performed a bimanual steering task, where they steered a cursor through a smooth W-shaped track of a certain width as quickly as possible while attempting to keep the cursor within the track. Task difficulty was altered by changing the track width and participants were split into one of the three groups based on the track width that they practiced on—wide, narrow, or progressive (where the width of the track progressively changed from wide to narrow over practice). The redundancy in this task arose from the fact that the position of the cursor was defined as the average position of the two hands. Results showed that movement time depended on task difficulty, but all groups were able to decrease their movement time with practice. Learning was associated with a reduction in null space variability in all groups, but critically, there was no effect of task difficulty. Further analyses showed that while the task-space variability showed an expected speed-accuracy tradeoff with movement time, the null space variability showed a qualitatively different pattern. These results suggest differential control of task and null space variability in response to changes in task difficulty with learning, and may reflect a strong preference to minimize overall movement variability during learning. [ABSTRACT FROM AUTHOR]

Research on children's prospective memory (PM) shows an increase of performance across childhood and provides first evidence that encoding strategies such as episodic future thinking (EFT; i.e., engaging in a vivid prospection of oneself performing future tasks) may improve performance. The present study aimed at testing whether the beneficial effects of EFT extend from typical lab-based tasks to more complex tasks with real life demands. Further, it was tested whether children's ability to project themselves into different perspectives (i.e., self-projection) moderates the effects of EFT encoding on PM. Overall, 56 children (mean age: M = 10.73 years) were included in this study who were randomly assigned to either an EFT or control condition. Children participated in a 'sightseeing tour' (ongoing activity) inside the lab with various socially relevant and neutral PM tasks embedded. Results showed significantly higher PM performance in the EFT compared to the control group. There was no difference between neutral and social PM tasks and no interaction between type of PM tasks with encoding condition. Further, self-projection did not moderate the effects of EFT encoding on PM. Results suggest that EFT is an effective strategy to improve children's everyday PM. These beneficial effects seem to occur independent from children's general ability to change perspectives and for different types of PM tasks. [ABSTRACT FROM AUTHOR]

In dual tasking, the no-go backward crosstalk effect (BCE) means that processing of Task 1 takes longer when Task 2 does not require a response (no-go trial) than when it requires a response (go trial). Thus, contrary to the usual observation, giving two successive responses counterintuitively reduces instead of increases performance costs for Task 1. Results from recent studies are in line with the notion that the no-go BCE reflects response inhibition, which is required to overcome an already prepared go response in Task 2, but which also spills over to motor execution in Task 1. No direct test of this hypothesis, however, has been carried out so far, and hence the present study was designed to fill this gap. The result of this study with n = 48 participants revealed that a no-go Task 2 impeded Task 1 performance when preparation of the Task 2 response was encouraged, but facilitated Task 1 performance when preparation of the Task 2 response was not encouraged. [ABSTRACT FROM AUTHOR]

The problem of partitioning systems of independent constrained-deadline sporadic tasks upon heterogeneous multiprocessor platforms is considered. Several different integer linear program (ILP) formulations of this problem, offering different trade-offs between effectiveness (as quantified by speedup bound) and running time efficiency, are presented. One of the formulations is leveraged to improve the best speedup guarantee known for a polynomial-time partitioning algorithm, from 12.9 to 7.83. Extensive computational results on synthetically generated instances are also provided to establish the effectiveness of the ILP formulations. [ABSTRACT FROM AUTHOR]

We performed complex electroencephalographic (EEG) and stabilographic study in 19 healthy volunteers (25 ± 0.7 years of age) performing isolated and simultaneous cognitive and motor tasks. Increased EEG coherence in the slow (Δ and θ) bands was observed predominantly in the frontotemporal areas of the left hemisphere during isolated computing-logical tasks. Increased coherence in slow spectral bands was also observed in the right hemisphere during spatial-visual tasks. During motor task performance, increased coherence in the high-frequency bands (α, β, and γ) was observed predominantly in the right hemisphere. The number of connections in the slow bands in simultaneous cognitive and motor tasks was decreased as compared with isolated tasks. Moreover, increased EEG coherence in the α1 band was observed in the frontal, central and parietal areas of both hemispheres during dual tasks. These findings can indicate the distribution of cognitive resources for both components of dual tasks, as well as the use of supplementary brain resources under these conditions. [ABSTRACT FROM AUTHOR]

In our daily life, we often encounter situations in which different features of several multidimensional objects must be perceived simultaneously. There are two types of environments of this kind: environments with multidimensional objects that have unique feature associations, and environments with multidimensional objects that have mixed feature associations. Recently, we (Goldfarb & Treisman, 2013) described the association effect, suggesting that the latter type causes behavioral perception difficulties. In the present study, we investigated this effect further by examining whether the effect is determined via a feedforward visual path or via a high-order task demand component. In order to test this question, in Experiment 1 a set of multidimensional objects were presented while we manipulated the letter case of a target feature, thus creating a visually different but semantically equivalent object, in terms of its identity. Similarly, in Experiment 2 artificial groups with different physical properties were created according to the task demands. The results indicated that the association effect is determined by the task demands, which create the group of reference. The importance of high-order task demand components in the association effect is further discussed, as well as the possible role of the neural synchrony of object files in explaining this effect. [ABSTRACT FROM AUTHOR]

The current article examined patterns of adult responding to arbitrary more-than and less-than relations across a range of real-world tasks. Previous research had reported weak performances on specific types of comparative relations presented in an automated task but also demonstrated that these could be significantly improved with feedback and nonarbitrary trial presentations. The current research sought to replicate these findings and explore the remediation of relational responding in more real-world tasks. The findings demonstrated that weaknesses in comparative relations were also recorded on these tasks, but feedback and nonarbitrary trials were equally effective in this context. The implications of the research for the further development of interventions for remediating deficits in relational responding are discussed. [ABSTRACT FROM AUTHOR]

Stable correlations between correction task characteristics and components of visual evoked potentials in response to light flash have been revealed. Faster task performance in males in comparison with females was established to be attained due to effective tuning and attuning of visual-motor system at the levels of specific and nonspecific systems related to visual analyzer. This determines potential for monotonous activity requiring constant visual attention. [ABSTRACT FROM AUTHOR]

Self-regulated learning has been described as an adaptive process: students adapt their learning strategies for attaining different learning goals. In order to be adaptive, students must have a clear notion of what the task requirements consist of. Both trace data and questionnaire data indicate that students adapt study strategies in limited ways and that their awareness of task demands seems to be low. In the present think-aloud study we examined task awareness of tenth-graders who selected text fragments in three different selection tasks. Students' task awareness was analysed at a global and a local task level. Awareness at the global task level refers to processing the instruction and reflecting about general selection goals; awareness at the local task level includes spontaneous reasoning about selecting specific text fragments. On either level, students showed difficulties in verbalizing task demands. In line with previous work, tenth-graders apparently experience a limited awareness of task demands. [ABSTRACT FROM AUTHOR]

part of action preparation is deciding what the relevant task is. This task-decision process is conceptually separate from response selection. To show this, the authors manipulated task conflict in a spatial task-switching paradigm, using conflict stimuli that appeared during trials with univalent targets (affording 1 task). The conflict stimuli afforded task identity because they were used as task cues with bivalent targets (affording 2 tasks) that were intermixed with the univalent targets. Thus, for univalent targets, irrelevant stimuli either caused low task conflict or high task conflict. In three experiments, the authors found poorer performance in high task conflict trials than in low task conflict trials. Task conflict was introduced during target appearance (Experiment 1) or task preparation (Experiments 2 and 3). In the latter case, the task conflict effect decreased with increasing task preparation time showing that task preparation involves task decision. [ABSTRACT FROM AUTHOR]

Two experiments examined training on a prospective time production task. Participants produced intervals, expressed in fixed arbitrary units, while performing a concurrent secondary task. After a 15-min filled delay, the participants were retrained on the same tasks. These experiments tested whether the primary and secondary tasks would be integrated into a single task. In Experiment 1, the secondary-task requirements were manipulated, but the time production task was fixed. In Experiment 2, the time production task requirements were manipulated, but the secondary task was fixed. The results suggest that participants integrate primary- and secondary-task requirements. [ABSTRACT FROM AUTHOR]

Task switching research has revealed that task changes lead to a performance switch cost. The present study focuses on the organization of task components in the task set. Three different views of task set organization have been distinguished and evidence in favor of each of these has been reported in the literature. In four experiments, we orthogonally varied the categorization task (magnitude and parity) and the stimulus dimension on which the categorization was to be made. Experiments 1,2, and 4 used Stroop-like number stimuli, whereas Experiment 3 used global-local stimuli to define the stimulus dimension. In Experiments 2-4, the cue-stimulus interval was also varied. The findings showed that a change of any component resulted in a cost, without any reliable difference in the size of these costs. These results are consistent with the flat view on task-set organization, which assumes that the task set binds all elements in an unstructured representation, which is completely reconfigured each time a change to the task set is required. The implications of these findings are discussed in relation to other findings and the different views on task-set organization. [ABSTRACT FROM AUTHOR]

In previous studies of task switching and of the right-left prevalence effect, researchers have used a procedure in which the stimulus on each trial occurs in one of four quadrants, and responses are made by pressing one of two diagonally arranged response keys. Across these studies, discrepant effects of cuing interval have been reported. These discrepancies need clarification because cue-based preparation effects are frequently interpreted as reflecting cognitive control processes. In Experiment I, we compared performance with display formats used by Meiran (1996; Meiran, Chorev, & Sapir, 2000; small display, cues located at sides of quadrants and displayed until response) to study task switching and by Proctor and colleagues (Proctor, Koch, & Vu, 2006; large display, cues located at center of display and shown until target onset) to study right-left prevalence. We found a decrease in task- switch cost with increasing cuing interval with the Meiran display, but not with the Proctor display, but the right-left prevalence effect was of similar size for the two display formats and was relatively unaffected by cuing interval. To determine the basis of the discrepant task-switch results, we used small and large displays in Experiments 2 and 3, respectively, with cue type and cue offset varied. With the side cues, the task-switch cost decreased in all cases at the longer cuing interval, but with the centered cues, it decreased only when the display size was small. Thus, the effects of cuing interval on switch costs are sensitive to variations of display characteristics, whereas cuing interval and display characteristics have little influence on the right-left prevalence effect, suggesting that prevalence effect is due to processes that are independent from those producing the switch cost. [ABSTRACT FROM AUTHOR]

Although a number of advanced theory of mind tasks have been developed, there is a dearth of information on whether performances on different tasks are associated. The present study examined the performance of 21 children and adolescents with diagnoses of Asperger syndrome (AS) and 20 typically developing controls on three advanced theory of mind tasks: The Eyes Task, the Strange Stories, and the Stories from Everyday Life. The participants in the clinical group demonstrated lower performance than the controls on all the three tasks. The pattern of findings, however, indicates that these tasks may share different information-processing requirements in addition to tapping different mentalizing abilities. [ABSTRACT FROM AUTHOR]

In this paper, I discuss whether in the Wason selection task, where subjects are asked to select evidence for evaluating a conditional, the most common response is indeed as irrational as many psychologists have maintained. My account of subjects' performances focuses on (i) how the task is understood by the subjects and (ii) whether their performances can be seen as cases not so much of conditional reasoning, as of hypothesis testing. On this basis and in accordance with Grice's account of indicative conditionals, I suppose that normally people understand the conditional as involving a "strong" connection between the antecedent and the consequent. Whenever the inference to such a connection is not blocked, subjects will inductively test whether it holds, as they do in ordinary life with reference to wider domains than the narrow one provided by the experimental context. Thus, relative to their goals, their performance could be considered as rational. [ABSTRACT FROM AUTHOR]

The scheduling component of the time management process was used as a "paradigm" to investigate the allocation of time to future tasks. In three experiments, we compared task time allocation for a single task with the summed time allocations given for each subtask that made up the single task. In all three, we found that allocated time for a single task was significantly smaller than the summed time allocated to the individual subtasks. We refer to this as the segmentation effect. In Experiment 3, we asked participants to give estimates by placing a mark on a time line, and found that giving time allocations in the form of rounded close approximations probably does not account for the segmentation effect. We discuss the results in relation to the basic processes used to allocate time to future tasks and the means by which planning fallacy bias might be reduced. [ABSTRACT FROM AUTHOR]

Often the performance of a task does not only require the processing of certain stimuli in certain ways, but also certain patterns of interlimb coordination. We studied shifts between different tasks involving different patterns of intermanual coupling by means of the timed-response procedure, which allows to trace state variables related to task sets. The tasks required the production of rapid bimanual reversal movements with symmetric or parallel directions. Symmetric movements are associated with symmetric coupling, as indicated by positive intermanual correlations between the directions of left-hand and right-hand movements, whereas parallel movements are associated with parallel coupling, as indicated by negative intermanual correlations. Task switches were associated with gradual changes of the intermanual correlations, which indicate the state of intermanual coupling as a major ingredient of a task set, in the course of action preparation. At short preparation intervals intermanual correlations were those appropriate for the preceding trial; with increasing preparation time they were replaced by those appropriate for the current trial, but the influence of the preceding trial did not disappear completely. In-between trials, intermanual coupling drifted toward a symmetric coupling, but not to uncoupled limbs. After a change of the task the specification of movement directions was slowed, but its initiation was not delayed. According to these results, task sets relax toward attractors which can be different from the absence of task sets. They are gradually configured during task preparation with a persistent influence of the preceding task, and the specification of response characteristics does not wait until the configuration of the new task set is completed. [ABSTRACT FROM AUTHOR]