Efficient Task Performance Research Articles

Learning Optimizes Decision Templates in the Human Visual Cortex

Translating sensory information into perceptual decisions is a core challenge faced by the brain. This ability is understood to rely on weighting sensory evidence in order to form mental templates of the critical differences between objects. Learning is shown to optimize these templates for efficient task performance, but the neural mechanisms underlying this improvement remain unknown. Here, we identify the mechanisms that the brain uses to implement templates for perceptual decisions through experience. We trained observers to discriminate visual forms that were randomly perturbed by noise. To characterize the internal stimulus template that observers learn when performing this task, we adopted a classification image approach (e.g., [5-7]) for the analysis of both behavioral and fMRI data. By reverse correlating behavioral and multivoxel pattern responses with noisy stimulus trials, we identified the critical image parts that determine the observers' choice. Observers learned to integrate information across locations and weight the discriminative image parts. Training enhanced shape processing in the lateral occipital area, which was shown to reflect size-invariant representations of informative image parts. Our findings demonstrate that learning optimizes mental templates for perceptual decisions by tuning the representation of informative image parts in higher ventral cortex.

Analysis of correlation between fractional amplitude of frequency fluctuation for resting-state fMRI and Go/Nogo task performance in undergraduate

Objective To investigate the correlation of spontaneous brain activity and Go/Nogo task performance with fractional amplitude of low-frequency fluctuation (fALFF)of the resting-state fMRI, and explore the functional basis of response inhibition. Methods Twenty-four college students were experienced resting-sate fMRI scans and Go/Nogo task and blood oxygenation level dependent (BOLD) signal and task behavioral performance were acquired to calculate the fractional amplitude of low-frequency fluctuation (fALFF)and intra-individual coefficient of variation(ICV). Pearson's correlation analysis between the fALFF values and the ICV was performed in a voxel-wise manner to get the significant fALFF-ICV correlation map(corrected, P<0.05). Results Significant negative fALFF-ICV correlations were observed in right gyrus rectus(BA11, r=-0.66), right superior frontal gyrus(BA10, r=-0.82), left mediate frontal(BA10, r=-0.80), left inferior frontal gyrus(BA45, r=-0.78), right inferior parietal lobule(BA2, r=-0.78), left supplementary motor area(BA6, r=-0.70) and right cerebellum(r=-0.63) .Significant positive fALFF-ICV correlations were observed in bilateral cuneus gyrus(BA18/19, r=0.68), left middle occipital cortex(BA19, r=0.73), left inferior occipital cortex(BA19, r=0.76) and bilateral lingual gyrus(BA17, r=0.77). Conclusion Close correlations between resting-state brain activities and Go/Nogo task performance are observed in the frontal cortex, supplementary motor area, posterior occipital lobe, cerebellum and some DMN regions.It is indicated that prefrontal cortex may have important influence on the efficiency of response inhibition, meanwhile, the default mode network may have possible influence on the efficiency of task performance. Key words: Resting-state functional magnetic resonance; Fractional amplitude of low frequency fluctuation; Go/Nogo task; Intra-individual coefficient of variation; Response inhibition

Improving video-mediated communication with orchestration

Video-mediated communication (VMC) has become a popular communication medium. However, research to date suggests that the inherent constraints of VMC impair effective and efficient communication and task performance. We propose that these negative findings could be attributed to how the technology was used and propose the novel concept of communication orchestration aimed at mitigating some of the signaled limitations. Orchestration is a selection process for displaying information that is deemed relevant for accomplishing an effective and efficient task performance and communicative experience. We report an experiment that confirmed this suggestion. The results indicate that orchestration could be an important novel feature to aid humans when communicating via VMC, but also suggest that there is potential for further improvements in orchestration.

Development and Validation of a Tool to Assess Emergency Physicians' Nontechnical Skills

Nontechnical skills are "the cognitive, social and personal resource skills that complement technical skills, and contribute to safe and efficient task performance." Our research team developed and evaluated the task of developing and validating a behavioral marker system for the observational assessment of emergency physicians' nontechnical skills. The development of the tool was divided into 3 phases and used triangulation of data from a number of sources. During phase 1, a provisional assessment tool was developed according to published literature and curricula. Phase 2 used analysis of staff interviews and field observations to determine whether the skill list contained any significant omissions. These studies were also used to identify behavioral markers linked to nontechnical skills in the context of the emergency department (ED) and establish whether skills included in the tool were observable. Phase 3 involved evaluating the content validity index of exemplar behaviors, using a survey of experts. A behavioral marker system was developed that comprised 12 emergency medicine-specific nontechnical skills, grouped into 4 categories. Content validity was assessed with a survey of 148 emergency medicine staff, and 75% of items achieved the recommended content validity index greater than 0.75. Data from the survey enabled further refinement of the behavioral markers to produce a final version of the tool. Although further evaluative studies are needed, this behavioral marker system provides a structured approach to the assessment and training of nontechnical skills in the ED.

Using E-Z Reader to simulate eye movements in nonreading tasks: A unified framework for understanding the eye–mind link.

Nonreading tasks that share some (but not all) of the task demands of reading have often been used to make inferences about how cognition influences when the eyes move during reading. In this article, we use variants of the E-Z Reader model of eye-movement control in reading to simulate eye-movement behavior in several of these tasks, including z-string reading, target-word search, and visual search of Landolt Cs arranged in both linear and circular arrays. These simulations demonstrate that a single computational framework is sufficient to simulate eye movements in both reading and nonreading tasks but also suggest that there are task-specific differences in both saccadic targeting (i.e., decisions about where to move the eyes) and the coupling between saccadic programming and the movement of attention (i.e., decisions about when to move the eyes). These findings suggest that some aspects of the eye-mind link are flexible and can be configured in a manner that supports efficient task performance.

What makes an orienteer an expert? A case study of a highly elite orienteer's concerns in the course of competition

This article reports a highly elite orienteer's cognitive activity over the course of two international competitions. We characterize the orienteer's concerns in relation to the problems raised during the competitions. The participant wore a head-mounted video camera throughout the competitions to enable the capture of an events record from the participant's perspective. During a post-performance self-confrontation interview, the participant was played the video and asked to describe his activity in relation to the events observed. The interview data were then used to identify the orienteer's concerns at each instant during the races. These “local” concerns were then compared and subsequently classified to characterize the typical concerns of the participant. Results showed three typical concerns: (a) find the controls faster than the opponents; (b) optimize running pace throughout the race; and (c) reflect on actions undertaken during performance. Results suggest the performer used a range of knowledge-driven strategies that enhanced the efficiency of task performance, and flexibly switched between strategies and decision-options in the face of presented changes in the task status. He also engaged in various reflective processes concurrent with performance that augmented the use of these strategies. In conclusion, this study provides insight into the cognitive processes underlying expert performance in sports characterized by decision-making under complexity, uncertainty, and time pressure.

How does starvation affect spatial organization within nests in Lasius niger?

Spatial distribution of ant workers within the nest is a key element of the colony social organization contributing to the efficiency of task performance and division of labour. Spatial distribution must be efficiently organized when ants are highly starved and have to get food rapidly. By studying ants’ behaviour within the nest during the beginning of food recruitment, this study demonstrates how the spatial organization is affected by starvation and improves the efficiency and the speed of recruitment as well as the allocation of food. (1) In starved nests, nestmates left the deep part of the nest and crowded near the nest entrance. This modification of the spatial distribution is a local phenomenon concerning only the individuals situated in the first chamber near the nest entrance. These starved individuals have a higher probability of leaving the nest after a contact with recruiters than nestmates situated deeper in the nest. This strongly suggests that nestmates situated near the nest entrance have a low response threshold to the signals emitted by recruiters. Their higher responsiveness speeds up their exit to the foraging area and hence may increase the efficiency of highly starved colonies in exploiting new food opportunities. (2) In starved nests, the trajectory covered by recruiters between contacts with nestmates was nearly twice as small. For recruiters, this represented a gain of time in the allocation of food. As the recruitment process follows snowball dynamics, this gain of time by starved recruiters might also speed up the exploitation of food. This study evidences how the spatial distribution of individuals as a function of their motivational state might have a regulatory function in the recruitment process, which should be generic for many social species.

Acute lecozotan administration increases learning and memory in rats without affecting anxiety or behavioral depression

Lecozotan is a selective serotonergic 5-HT 1A receptor antagonist previously shown to enhance task performance efficiency in aged rhesus monkeys. In the present report we tested the ability of this drug to modify memory and learning in rats during a modified passive avoidance response test, and also tested its effect on anxiety with the elevated plus maze, and behavioral depression in the inescapable swim test. Lecozotan enhanced memory in a dose-dependent manner (0, 0.3, 0.5, 1 and 2 mg/kg; s.c.), or prevented memory impairment previously induced with scopolamine-HCl. No significant changes in anxiety and behavioral depression were detected in animals treated with different doses of lecozotan (0, 0.3, 1 and 2 mg/kg; s.c.) compared to control animals. These results suggest that lecozotan could enhance learning and memory in animals without affecting anxiety or behavioral depression scores and that it could be a viable alternative in the treatment of patients with cognitive deficits such as the Alzheimer's disease.

Consequences of sleep deprivation

This paper presents the history of research and the results of recent studies on the effects of sleep deprivation in animals and humans. Humans can bear several days of continuous sleeplessness, experiencing deterioration in wellbeing and effectiveness; however, also a shorter reduction in the sleep time may lead to deteriorated functioning. Sleeplessness accounts for impaired perception, difficulties in keeping concentration, vision disturbances, slower reactions, as well as the appearance of microepisodes of sleep during wakefulness which lead to lower capabilities and efficiency of task performance and to increased number of errors. Sleep deprivation results in poor memorizing, schematic thinking, which yields wrong decisions, and emotional disturbances such as deteriorated interpersonal responses and increased aggressiveness. The symptoms are accompanied by brain tissue hypometabolism, particularly in the thalamus, prefrontal, frontal and occipital cortex and motor speech centres. Sleep deficiency intensifies muscle tonus and coexisting tremor, speech performance becomes monotonous and unclear, and sensitivity to pain is higher. Sleeplessness also relates to the changes in the immune response and the pattern of hormonal secretion, of the growth hormone in particular. The risk of obesity, diabetes and cardiovascular disease increases. The impairment of performance which is caused by 20-25 hours of sleeplessness is comparable to that after ethanol intoxication at the level of 0.10% blood alcohol concentration. The consequences of chronic sleep reduction or a shallow sleep repeated for several days tend to accumulate and resemble the effects of acute sleep deprivation lasting several dozen hours. At work, such effects hinder proper performance of many essential tasks and in extreme situations (machine operation or vehicle driving), sleep loss may be hazardous to the worker and his/her environment.

Sex differences in prefrontal hemodynamic response to mental arithmetic as assessed by near-infrared spectroscopy

Sex differences in cognitive tasks have been widely investigated. With brain-imaging techniques, the functions of the brain during the performance of tasks can be examined. Mental arithmetic and near-infrared spectroscopy (NIRS) were used to assess sex differences in prefrontal area activation in a functional brain study. Healthy college students were recruited to perform 2 mental arithmetic tasks. In the first (easy) task, students had to subtract a 1-digit number from a 3-digit number. In the second (difficult) task, they had to subtract a 2-digit number from a 3-digit number. Changes in the concentration of oxygenated hemoglobin (oxy-Hgb) in the prefrontal area during the tasks were measured with NIRS. Thirty students (15 men, 15 women; mean [SD] age: 24.9 [2.2] and 24.3 [2.6] years, respectively) were recruited from Southeast University, Nanjing, China, to participate in the study. The concentration of oxy-Hgb increased during both mental arithmetic tasks (difficult task vs easy task, mean [SD] % arbitrary units: 4.36 [4.38] vs 2.26 [2.82]; F(1,28) = 222.80; P < 0.01). Significant interactions of task x sex (F(1,28) = 82.95), time x sex (F(1,28) = 34.48), task x time (F(1,28) = 222.57), and task x time x sex (F(1,28) = 83.09) were obtained (all, P < 0.01). However, for the 2 tasks, no significant differences between men and women were observed in the mean (SD) response time (men vs women, sec: 3.60 [0.74] vs 3.56 [0.49] for the easy task, 6.55 [0.77] vs 6.44 [0.75] for the difficult task; F(1,28) = 0.67; P = NS) or accuracy rate (men vs women, %: 95.33 [7.40] vs 92.77 [8.80] for the easy task, 62.67 [28.56] vs 54.67 [18.75] for the difficult task; F(1,28) = 0.54; P = NS). Male students showed neural efficiency (less prefrontal activation in subjects with better performance) during the difficult task. In these subjects, sex differences in prefrontal response when performing mental arithmetic were associated with the intensity of the task. Compared with men, women had greater efficiency in task performance (ie, less activation or oxygen consumption for equal performance).

Operational “Feel” Adjustment by Reinforcement Learning for a Power-Assisted Positioning Task

Controlling “feel” when operating a power-assist robot is important for improving robot operability, user satisfaction, and task performance efficiency. Autonomous adjustment of “feel” is considered with robots under impedance control, and reinforcement learning in adjustment when a task includes repetitive positioning is discussed. Experimental results demonstrate that an operational “feel” pattern appropriate for positioning at a goal is developed by adjustment. Adjustment assuming a single fixed goal is expanded to cases including multiple goals, in which it is assumed that one goal is chosen by a user in real time. To adjust operational “feel” to individual goals, an algorithm infers the goal. The same result as that for a single fixed goal is obtained in experiments, but experimental results suggest that design must be improved to where the accuracy of inference to the goal is taken into account by the adjustment learning algorithm.

The TIP Theory: Prescriptions for Designing Instruction for Teams

The purpose of the Team Instructional Prescriptions (TIP) theory is to prescribe a set of systematically integrated principles for designing instruction for teams. The structure of the theory is based on Reigeluth and Merrill's conditions–methods–outcomes framework. The TIP theory identifies two interrelated instructional outcomes: effective, efficient teamwork, and effective, efficient team task performance. These outcomes can be attained by prescribing concurrent instructional methods for both team development and task performance. The selection of instructional methods (specifically organizational strategies) is determined by three sets of condition variables: (1) team development stages (forming, performing I, and performing II); (2) task process dimensions (procedural/interdependent, procedural/independent, transfer/interdependent, and transfer/independent); and (3) task relationships (subordinate, coordinate, and superordinate). These three sets of conditions define 36 unique instructional conditions, each of which requires a slightly different set of organizational strategies (macro, mid–level, and micro).

Daily activities, cognition and community functioning in persons with schizophrenia

Objective This cross-sectional study explored the relationships between daily activity performance, attention, memory, executive functions and community functioning in people with schizophrenia. More specifically, this study attempted to verify the hypothesis that functional limitations in the performance of daily activities negatively affect community functioning in people with schizophrenia. Methods Eighty-two individuals with schizophrenia living in the community were recruited for the study. The Perceive, Recall, Plan and Perform (PRPP) System of Task Analysis was used to assess participants’ functional capacity during a meal preparation task. Visuo-spatial associative memory, spatial working memory, planning, visuo-motor coordination, and selective attention were evaluated as well. Community functioning was assessed with the Independent Living Skills Survey (ILSS) and the Multnomah Community Ability Scale (MCAS). Results Correlations revealed significant associations between functional capacity and visuo-spatial associative learning, spatial working memory, planning and negative symptoms. Planning skills during meal preparation were found to be associated with MCAS. After regression analyses, only visuo-spatial memory, negative symptoms, education and familiarity with meal preparation explained variation in functional capacity. Conclusions The findings of the current study suggest that visuo-spatial associative learning, negative symptoms, education and familiarity with task are among the important factors for functional capacity. Planning skills necessary for efficient task performance were also found to be those most determinant for community functioning. Rehabilitation interventions should consider these underlying strength and deficits when developing strategies to help people with schizophrenia build functional skills essential for community living.

System for infectious disease information sharing and analysis: design and evaluation.

Motivated by the importance of infectious disease informatics (IDI) and the challenges to IDI system development and data sharing, we design and implement BioPortal, a Web-based IDI system that integrates cross-jurisdictional data to support information sharing, analysis, and visualization in public health. In this paper, we discuss general challenges in IDI, describe BioPortal's architecture and functionalities, and highlight encouraging evaluation results obtained from a controlled experiment that focused on analysis accuracy, task performance efficiency, user information satisfaction, system usability, usefulness, and ease of use.

Evaluation of presentation of information for process control operations

In an experimental process control simulation study two operators performed monitoring and control operations including safety critical tasks that required parallel processing of information distributed over different functional mimic displays. The assignment of mimic displays to Visual Display Units (VDUs) was experimentally varied by allowing one or two VDUs for mimic presentation. The study revealed no evidence for differences in task performance during normal process control operations. During abnormal operations, however, detrimental effects both on performance and work load were observed. Having only one VDU available for mimic display revealed either a lower level of performance (time for fault management) and/or a higher level of emotional work strain. It is concluded that decisions on the number of VDUs necessary for effective and efficient process control must refer to the tasks to be performed and the presentation of information necessary for a safe, effective and efficient task performance under critical, but not only normal conditions.

Comparison of surgical performance during laparoscopic radical prostatectomy of two robotic camera holders, EndoAssist and AESOP: A pilot study

Objectives Robotic camera holders provide steady camera movement and view during laparoscopic surgery. We compared two such robots, EndoAssist and AESOP, by evaluating timed setup and surgical performance during laparoscopic radical prostatectomy (LRP). Methods We prospectively collected data for 20 patients undergoing LRP using either the EndoAssist or AESOP. AESOP was mounted to the surgical bed and controlled by an experienced assistant using a hand-held remote control. The EndoAssist device was placed over the patient’s right shoulder. Its movements were executed by the surgeon using a head-mounted optical emitter with brief head movements detected by a sensor mounted atop the surgeon’s video monitor. The robot setup time and LRP operative steps were timed and compared between the two cohorts. Results The time for robot setup favored AESOP over the EndoAssist (2.0 minutes versus 5.3 minutes, P = 0.001). The time for accomplishing vas deferens and seminal vesicle dissection favored the EndoAssist (23 minutes versus 33 minutes, P = 0.04). However, no statistically significant difference was found in the efficiency of task performance between the two robots in any of the other 11 steps measured. Conclusions The EndoAssist appears to be equally efficient to the assistant-controlled AESOP robot with respect to surgical performance during LRP. The advantages of the EndoAssist include its accurate response and ability to provide the surgeon with complete control of the desired operative view without relying on an assistant. Its disadvantages include its large profile, lack of a table-mounted design, and the need for pedal activation. Additional modifications are needed to improve the efficiency and design of this novel robotic device further.

Spatial organization in a dimorphic ant: caste specificity of clustering patterns and area marking

Living in groups constitutes the root of social organization in animals. Likewise, the spatial aggregation between members of insects societies plays a crucial role in social cohesion and division of labor, namely, in polymorphic ant species. In the present paper, we show caste-specific aggregation patterns in the strictly dimorphic Pheidole pallidula ant species. We investigate the influence on the clustering of ants exerted by direct contacts between nest mates as well as by indirect cues through chemical marking. In a homogeneous environment deprived of chemical cues, majors show a higher aggregation level than minors and a centripetal behavior. By contrast, minors are more scattered in the experimental arena and display a centrifugal behavior. In addition, area marking laid by minors enhances their own aggregative behavior while contributing to the localization of the spontaneously aggregating majors. Such differences in aggregative patterns as well as their adaptive value have to be coupled with the mobility level and the task performance efficiency of each worker caste. Contrary to majors that are likely to aggregate, highly mobile minors, scattered inside and outside the nest colony, can detect colony needs and can carry out most of the daily tasks for which they are more efficient than majors.

How brood influences caste aggregation patterns in the dimorphic ant species Pheidole pallidula

Spatial distribution of ant workers and, notably their aggregation/segregation behaviour, is a key-element of the colony social organization contributing to the efficiency of task performance and division of labour. In polymorphic species, specialized worker castes notably differ in their intrinsic aggregation behaviour. In this context, knowing the preponderant role of minors in brood care, we investigate how a stimulus such as brood can influence the spatial patterns of Pheidole pallidula worker castes. In a homogeneous area without brood, it was shown that minors display only a low level of aggregation while majors form large clusters in the central area. Here we find out that these aggregation patterns of both minors and majors can be deeply influenced by the presence of brood. For minors, it nucleates or enhances the formation of a large stable cluster. Such high sensitivity of minors to brood stimuli fits well with their role as main brood tenders in the colony. For majors, interattraction between individuals still remains the prevailing aggregation factor while brood strongly influences the localisation of their cluster. We discuss how the balance between interattraction and sensitivity to environmental stimuli determines the mobility of each worker castes and, consequently, the availability of minors and majors to participate in everyday colony tasks. Moreover, we will evoke the functional value of majors’ cluster location close to the brood, namely with respect to social regulation of the colony caste ratio.

Using advance information in dynamic cognitive control: An ERP study of task-switching

Ensuring that behavior remains appropriate over time requires dynamic, flexible control. We used the task-switching procedure to investigate the mechanisms whereby advance information is used to control behavior under conditions of frequently changing task-rules. The color of target stimuli signaled which task-set (or behavioral ‘rule’) was required on each trial. We provided different forms of advance information in two conditions and found a double dissociation in their effects: visual precues (‘precueing’) facilitated task-switching, whereas a fixed task-sequence (‘predictability’) facilitated task-repetition. In addition, precueing was associated with a late parietal positive ERP which preceded target onset, whereas predictability produced an increase in the target-locked centro-parietal P3b ERP. We suggest that these results indicate the activity of two distinct mechanisms. The first, driven by a task-cue and indexed by the late parietal positivity, may drive efficient task-performance on precued switch trials but occurs too late on non-precued switch trials to index an anticipatory task-set reconfiguration process. The second may constitute active consolidation or maintenance of a particular task-set which occurs at least one trial ahead, when task-repetitions are predictable, and results in facilitation of target stimulus evaluation.

Absent-mindedness: Lapses of conscious awareness and everyday cognitive failures

A brief self-report scale was developed to assess everyday performance failures arising directly or primarily from brief failures of sustained attention (attention-related cognitive errors—ARCES). The ARCES was found to be associated with a more direct measure of propensity to attention lapses (Mindful Attention Awareness Scale—MAAS) and to errors on an existing behavioral measure of sustained attention (Sustained Attention to Response Task—SART). Although the ARCES and MAAS were highly correlated, structural modelling revealed the ARCES was more directly related to SART errors and the MAAS to SART RTs, which have been hypothesized to directly reflect the lapses of attention that lead to SART errors. Thus, the MAAS and SART RTs appear to directly reflect attention lapses, whereas the ARCES and SART errors reflect the mistakes these lapses are thought to cause. Boredom proneness was also assessed by the BPS, as a separate consequence of a propensity to attention lapses. Although the ARCES was significantly associated with the BPS, this association was entirely accounted for by the MAAS, suggesting that performance errors and boredom are separate consequences of lapses in attention. A tendency to even extraordinarily brief attention lapses on the order of milliseconds may have far-reaching consequences not only for safe and efficient task performance but also for sustaining the motivation to persist in and enjoy these tasks.