Low Task Difficulty Research Articles

Determining the optimal challenge point for learning motor skills in children with attention deficit/hyperactivity disorder

The purpose of this study was to investigate the optimal challenge point for learning motor skills in children with and without attention deficit/hyperactivity disorder (ADHD). Ninety-six 9- to 10-year-old children, including 48 children with ADHD and 48 neurotypical children, were randomly assigned to one of four practice groups with varying levels of nominal and functional task difficulty. They performed 63 trials of a dart throwing task in the acquisition phase and 18 trials in the retention and transfer tests a day later. The results showed that neurotypical children outperformed children with ADHD in all phases of the study. Both groups improved in the acquisition phase and performed better in the retention and transfer tests. Interestingly, low nominal task difficulty was associated with better learning for both groups, despite lower average performance for children with ADHD. Thus, despite their performance differences, we did not find a difference in the effective challenge point between children with ADHD and their neurotypical peers.

Visual Function After Implantation of Trifocal and Trifocal Toric Intraocular Lenses Using Intraoperative Aberrometry.

To evaluate patient outcomes and visual function following trifocal and trifocal toric intraocular lens (IOL) implantation using intraoperative aberrometry at a single site in the US. This prospective, single arm study included 21 subjects that completed 3 month follow-up. Inclusion criteria were visually significant cataract and potential post-operative visual acuity of 20/25 or better. Endpoints included postoperative prediction error, refractive outcomes, uncorrected visual acuities at distance (UDVA), intermediate (UIVA), and near (UNVA), contrast sensitivity, and subject responses on the modified Visual Function Quality of Life Questionnaire (VF-14 QOL). Binocular UDVA, UIVA, and UNVA were 20/25 or better in 100% (21/21), 100% (21/21), 90% (19/21) of subjects. The absolute prediction error was 0.50 D or less in 79% (33/42) of eyes, and 81% (34/42) and 86% (36/42) of eyes achieved ≤0.5 D of residual astigmatism and manifest refraction spherical equivalent, respectively. On the modified VF-14 QOL, driving at night, reading small print, and reading a newspaper or book were the tasks that had the lowest percentages of subjects reporting no difficulty or a little difficulty. Implantation with trifocal and trifocal toric IOLs using intraoperative aberrometry can provide high refractive precision, leading to excellent visual performance and low visual task difficulty at all ranges (distance, intermediate, and near).

Evaluation of physiological responses to mental workload in n-back and arithmetic tasks

Working memory tasks, such as n-back and arithmetic tasks, are frequently used in studying mental workload. The present study investigated and compared the sensitivity of several physiological measures at three levels of difficulty of n-back and arithmetic tasks. The results showed significant differences in fixation duration and pupil diameter among three task difficulty levels for both n-back and arithmetic tasks. Pupil diameters increase with increasing mental workload, whereas fixation duration decreases. Blink duration and heart rate (HR) were significantly increased as task difficulty increased in the n-back task, while root mean square of successive differences (RMSSD) and standard deviation of R-R intervals (SDNN) were significantly decreased in the arithmetic task. On the other hand, blink rate and Galvanic Skin Response (GSR) were not sensitive enough to assess the differences in task difficulty for both tasks. All significant physiological measures yielded significant differences between low and high task difficulty except for SDNN. Practitioner summary: This study aimed to assess the sensitivity levels of several physiological measures of mental workload in n-back and arithmetic tasks. It showed that pupil diameter was the most sensitive in both tasks. This study also found that most physiological indices are sensitive to an extreme change in task difficulty levels.

The Effects of Visual Complexity and Task Difficulty on the Comprehensive Cognitive Efficiency of Cluster Separation Tasks.

Cluster separation is required to perform multi-class visual statistics tasks and plays an essential role in information processing in visualization. This cognition behavioral study investigated the cluster separation task and the effects of visual complexity and task difficulty. A total of 32 college students (18 men and 14 women, with ages ranging from 18 to 25 years; mean = 21.2, SD = 3.9) participated in this study. The observers' average response accuracy, reaction time, mental effort, and comprehensive cognitive efficiency were measured as functions of three levels of visual complexity and task difficulty. The levels of visual complexity and task difficulty were quantified via an optimized complexity evaluation method and discrimination judgment task, respectively. The results showed that visual complexity and task difficulty significantly influenced comprehensive cognitive efficiency. Moreover, a strong interaction was observed between the effects of visual complexity and task difficulty. However, there was no positive linear relationship between the mental effort and the complexity level. Furthermore, two-dimensional color × shape redundant coding showed higher cognitive efficiency at low task difficulty levels. In contrast, the one-dimensional color encoding approach showed higher cognitive efficiency at increased task difficulty levels. The findings of this study provide valuable insights into designing more efficient and user-friendly visualization in the future.

Effects of manipulator operation task and troubleshooting task on blood pressure indexes of oceanauts

Objective: To explore the characteristics and rules of blood pressure changes in oceanauts during simulated operation of manipulator and troubleshooting tasks with different difficulty. Methods: In July 2020, 8 deep-sea manned submersible oceanauts, 6 males and 2 females, were selected as objects. In the 1∶1 model of Jiaolong deep-sea manned submersible, the oceanauts performed manipulator operation tasks and troubleshooting tasks with different difficulties, measured the continuous blood pressure of the oceanauts, filled in the NASA Task Load Index (NASA-TLX scale) after the completion of a single mission, and the changes of systolic pressure (SBP), diastolic pressure (DBP), mean arterial pressure (MAP) and mental workload were analyzed. Results: In a single task, the SBP, DBP and MAP of the oceanauts increased first and then decreased. The blood pressure values at the third minute were significantly lower than those at the first minute (P<0.01), and those at the fifth minute were significantly higher than those at the third minute (P<0.01). When performing the same task, compared with the quiet state, SBP, DBP and MAP increased when the oceanauts performed low difficulty, high difficulty, high difficulty+2-back manipulator operation task and troubleshooting task (P<0.05). When the task difficulty was the same, the SBP and MAP of oceanauts performing manipulator operation tasks were higher than those of oceanauts performing troubleshooting tasks (P<0.05). Compared with low difficulty tasks, the scores of NASA-TLX scale for oceanauts performing high difficulty manipulator operationtasks were significantly higher (P<0.05). Compared with the low difficulty task and high difficulty task, the scale score of the high difficulty+2-back troubleshooting task was significantly higher (P<0.05). When the task difficulty was the same, the scale scores of low difficulty and high difficulty manipulator operation tasks were significantly higher than those of troubleshooting tasks (P<0.05). SBP, DBP, MAP of No. 1, No. 3, No. 4, No. 5, and No. 7 oceanauts (all of whom had 6 years of diving) were positively correlated with NASA-TLX scale scores (r>0.8, P<0.05) . Conclusion: In the process of manned deep-sea diving, when the oceanauts perform manipulator operation tasks and troubleshooting tasks, with the increase of task difficulty, the mental load of oceanauts increases, and the blood pressure index increases significantly in a short time. At the same time, improving the proficiency of operation can reduce the variation range of blood pressure indexes. Blood pressure can be used as an effective reference to evaluate the difficulty of operation and guide scientific training.

Lighting color temperature impacts effort-related cardiovascular response to an auditory short-term memory task

To better understand the impact of environmental light on processes that underlie cognitive activity, Lasauskaite and Cajochen (2018) recently proposed a theoretical model that predicts how light's correlated color temperature (CCT) affects effort. Here we tested whether the effects of CCT of light on effort-related cardiovascular response also extend to another sensory input—hearing. In two experimental blocks, participants were exposed to either low (2800 K) or high correlated color temperature (6500 K) light with an illumination level of 500 lux for 15 min before and while they performed an auditory n-back task varying in difficulty level (low difficulty/1-back vs. moderate difficulty/2-back). Mental effort was indexed as sympathetic beta-adrenergic impact on the heart, measured via cardiac pre-ejection period and systolic blood pressure. Based on the theoretical model, we hypothesized that light with a high CCT should lead to lower mental effort compared to light with a low CCT in both the low and moderate task difficulty conditions. Moreover, moderate task difficulty should lead to stronger effort compared to an easy task. The results did not show expected differences in invested effort levels between the task difficulty conditions (1-back vs. 2-back task) measured by cardiac pre-ejection period and systolic blood pressure. However, in line with our prediction, the results indicated that higher CCT of light decreased effort during an auditory memory task. Task performance was higher in easy than moderate task difficulty but was not altered by lighting conditions. Furthermore, we found no significant associations between cardiovascular reactivity and changes in mood, sleepiness, light, task, or effort ratings. Taken together, our results provide first evidence that higher CCT of light reduces the amount of effort invested during cognitive tasks for which hearing is needed. Given that this study was conducted under controlled laboratory conditions and with healthy young participants, additional research is needed to demonstrate that our results generalize to real-life applications. Nevertheless, we recommend that lower CCT of light should be avoided in learning and work contexts, as it might lead to higher effort and cardiovascular reactivity that may contribute to the development of cardiovascular health problems. Instead, we recommend higher CCT of light during daytime for wellbeing and health.

Motor-induced oscillations in choice response performance.

Recently, numerous studies have revealed 4-12 Hz fluctuations of behavioral performance in a multitude of tasks. The majority has utilized stimuli near detection threshold and observed related fluctuations in hit-rates, attributing these to perceptual or attentional processes. As neural oscillations in the 8-20 Hz range also feature prominently in cortical motor areas, they might cause fluctuations in the ability to induce responses, independent of attentional capabilities. Additionally, different effectors (e.g., the left versus right hand) might be cyclically prioritized in an alternating fashion, similar to the attentional sampling of distinct locations, objects, or memory templates. Here, we investigated these questions via a behavioral dense-sampling approach. Twenty-six participants performed a simple visual discrimination task using highly salient stimuli. We varied the interval between each motor response and the subsequent target from 330 to 1040 ms, and analyzed performance as a function of this interval. Our data show significant fluctuations of both RTs and sensitivity between 12.5 and 25 Hz, but no evidence for an alternating prioritization of left- versus right-hand responses. While our results suggest an impact of motor-related signals on performance oscillations, they might additionally be influenced by perceptual processes earlier in the processing hierarchy. In summary, we demonstrate that behavioral oscillations generalize to situations involving highly salient stimuli, closer to everyday life. Moreover, our work adds to the literature by showing fluctuations at a high speed, which might be a consequence of both low task difficulty and the involvement of sensorimotor rhythms.

Benefits of Decision Support Systems in Relation to Task Difficulty in Airport Security X-Ray Screening

Automated explosive detection systems for cabin baggage screening (EDSCB) highlight areas in X-ray images of passenger bags that could contain explosive material. Several countries have implemented EDSCB so that passengers can leave personal electronic devices in their cabin baggage. This increases checkpoint efficiency, but also task difficulty for screeners. We used this case to investigate whether the benefits of decision support systems depend on task difficulty. 100 professional screeners conducted a simulated baggage screening task. They had to detect prohibited articles built into personal electronic devices that were screened either separately (low task difficulty) or inside baggage (high task difficulty). Results showed that EDSCB increased the detection of bombs built into personal electronic devices when screened separately. When electronics were left inside the baggage, operators ignored many EDSCB alarms, and many bombs were missed. Moreover, screeners missed most unalarmed explosives because they over-relied on the EDSCB’s judgment. We recommend that when EDSCB indicates that the bag might contain an explosive, baggage should always be examined further in a secondary search using explosive trace detection, manual opening of bags and other means.

과제 난이도에 따른 연속적인 조준 동작의 제어 특성

The present study investigated characteristics on the control of continuous aiming movements in index of difficulty (i.e., task difficulty). In this study, 39 participants were instructed to perform continuous aiming movement to specified targets across three task difficulty (i.e., low accuracy, normal accuracy, and high accuracy constraints). The characteristics of the movement speed in performing the continuous aiming motion according to the three task difficulty levels were collected. The results showed that the movement speed was the slowest in the high task difficulty level, and the movement pattern fluctuation was the largest. On the other hand, the movement performance speed was the fastest in the low task difficulty level, and the movement pattern fluctuations were also the smallest. These results suggest that as the task difficulty increases, it is difficult to control the muscle torque of the limbs in performing continuous aiming movements. In addition, it is shown that the higher the task difficulty, the lower the movement speed in order to increase the accuracy of the movement in performing continuous aiming movements.

The Effects of Academic Self-Efficacy on College Life Satisfaction of Taekwondo University Students in Untact COVID-19

This study was conducted to investigate the relationship between academic self-efficacy and college life satisfaction of University students in Taekwondo department in the era of untact COVID-19. For this purpose, 362 students in department of Taekwondo and As a result of analysis using SPSS ver .25.0, first. As a result of examining the difference in the academic self-efficacy of students in Taekwondo department, it was found that there was a significant difference only in preference for low task difficulty for both gender and grade level. Second, there was a significant difference only in overall college life and learning satisfaction. Third, it was found that self-regulation and confidence factors had a positive effect on college education and administrative service factors, and low task difficulty factors had a negative effect. On the overall college life satisfaction factors, only the low task difficulty factors had a negative effect It was found that only the self-regulation factor had a significant effect on learning satisfaction and school satisfaction.

Revision of motivation for choosing teacher education scale-preservice teachers specializing in physical education at the secondary level and its reliability and validity testing

&lt;p&gt;目的：本研究藉由酌修張炳煌 (2017) 翻譯修訂之「中文版師資培育學程選擇動機量表」(Chinese version of the Motivation for Choosing Teacher Education Scale, C-FEMOLA) 題項的用字遣詞，並酌減C-FEMOLA題項的數量，進一步將C-FEMOLA修訂成中等學校體育師資生「師資培育學程選擇動機量表」(motivation for choosing teacher education scale-preservice teachers specializing in physical education at the secondary level, MCTES-PTSPESL)，並檢驗其信度與效度。方法：藉由國立臺灣體育運動大學126位體育師資生為研究對象，針對研究樣本透過問卷調查的方式蒐集相關資料，接著進行項目分析、試探性因素分析與驗證性因素分析，並計算Cronbach&amp;rsquo;s &amp;alpha;係數，以檢驗MCTES-PTSPESL的信度與效度。結果：在個別題項的適切性方面，項目分析發現，MCTES-PTSPESL個別題項的適切性佳，21個題項皆予以保留。在效度方面，試探性因素分析與驗證性因素分析皆發現，MCTES-PTSPESL包含「自我能力信念」、「任務難度較低」、「主修科目興趣」、「教育興趣」、「社會影響」、「經濟效用性」及「時間效用性」等七個分量表，具有良好的構念效度。在信度方面，七個分量表的&amp;alpha;值介於.67至.90；總量表的&amp;alpha;值為.87。結論：MCTES-PTSPESL具有良好的信度與效度，適合用來測量中等學校體育師資生師資培育學程選擇動機。&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;p&gt;Objective: This study used the items of the Chinese version of the Motivation for Choosing Teacher Education Scale (C-FEMOLA) as the basis and reduced the number of items in C-FEMOLA from 30 to 21. The modified C-FEMOLA was subsequently revised into the Motivation for Choosing Teacher Education Scale&amp;mdash;Preservice Teachers Specializing in Physical Education at the Secondary Level (MCTES-PTSPESL), reliability and validity of which were tested. Methods: The research participants consisted of 126 preservice teachers studying in National Taiwan University of Sport. This study used the questionnaire survey method to collect data. Item analysis, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were conducted on the research sample. In addition, Cronbach&amp;rsquo;s &amp;alpha; coefficients were calculated to validate the reliability and validity of MCTES-PTSPESL. Results: Item analysis results revealed that the individual items of MCTES-PTSPESL exhibited high relevance and the 21 items were all preserved. The EFA and CFA results revealed that MCTES-PTSPESL contained 7 subscales, namely, ability beliefs, low task difficulty, subject-specific interest, educational interest, social influence, financial utility, and time compatibility utility, all of which exhibited favorable construct validity. The Cronbach&amp;rsquo;s &amp;alpha; values of the 7 subscales were between .67 and .90 and the Cronbach&amp;rsquo;s &amp;alpha; value of the scale was .87. Conclusion: MCTES-PTSPESL exhibited favorable reliability and validity and is suitable for measuring motivation for choosing teacher education programs among preservice teachers specializing in physical education at the secondary education level.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Biomechanical differences between military patients with patellar tendinopathy and asymptomatic controls during single-leg squatting and gait – A statistical parametric mapping study

BackgroundPrior identification of biomechanical differences between patients with patellar tendinopathy and healthy controls has utilised time-discrete analysis which is susceptible to type I error when multiple comparisons are uncorrected. We employ statistical parametric mapping to minimise the risk of such error, enabling more appropriate clinical decision-making. MethodsLower-limb biomechanics of 21 patients with patellar tendinopathy and 22 controls were captured during walking and three types of squats. A statistical parametric mapping two-sample t-test was used to identify kinematic and kinetic differences between groups for each joint. Paired t-tests were used to compare pain before and after tasks, in patients with patellar tendinopathy. FindingsDuring walking, cases demonstrated reduced knee joint power during initial contact and hip joint power during terminal stance. In squatting, cases demonstrated increased knee abduction angles at various time points of the small knee bend and single-leg squat. Cases demonstrated reduced knee internal rotation moment during the deepest portion of the single-leg squat and single-leg decline squat. InterpretationGait appears unaffected by patellar tendinopathy, likely due to low task difficulty. Elevated knee abductions angles during squatting were confirmed as a key difference in patients with patellar tendinopathy. Reduced knee internal rotation moments in patients were attributed to a potential reduction in hip external rotator strength and possible pain avoidance strategy; however further evidence is required to substantiate these claims. Findings provide a clear rationale for rehabilitation programs to focus on knee stabilisation and strengthening of the muscles surrounding the hip.

Problem-solving deficits in methcathinone use disorder

The use of methcathinone (MCAT), a psychostimulant drug that can lead to long-term health risks and executive dysfunction, increased to an alarming rate in recent years. Impairments in low-level executive function have been reported in substance use disorder. However, little empirical evidence is available regarding high-level executive function (e.g., problem solving), which may act as a risk factor for relapse. The present study aimed to investigate whether the problem-solving ability was altered in abstinent individuals with methcathinone use disorder (MCUD). Here, we tested fifty male MCUD individuals (short-term MCUD group: twenty-nine patients with MCAT use less than 3years, long-term MCUD group: twenty-one patients with MCAT use longer than 3years, which were split by medium years of drug use) and twenty-four well-matched healthy controls (HC) in the Tower of Hanoi task (TOH) to assess the impact of task difficulty on drug-related changes in problem-solving performance. We used several measures to characterize problem-solving performance: the number of mistakes made, the completion time of the task, and the thinking time before the first move. In the low task difficulty condition, the MCUD group and HC group showed similar levels of mistakes and completion time, while in the high task difficulty condition, the MCUD group reported more mistakes (the mean number of mistakes in each trial: 1.41 ± 1.15 vs 0.79 ± 0.76, P = 0.019, Cohen's d = 0.635) and longer completion time in the task (the mean completion time in each trial: 45.83 ± 20.51s vs 33.40 ± 15.10s, P = 0.010, Cohen's d = 0.690) than the HC group. The thinking time before the first move did not differ significantly between groups (P = 0.257). We further found that the long-term (more than 3years) MCUD group made more mistakes than the short-term MCUD group and HC group, mainly in the highly difficult subtasks. The longer time than HCs was reported in the long-term MCUD group among high task difficulty of subtasks. In addition, there was a positive correlation between years of MCAT use and the number of mistakes made in high task difficulty TOH task (r = 0.326, P = 0.021). Chronic methcathinone use was associated with deficits in problem-solving performance, which depended on the degree of task difficulty. The impairment was more evident in the long-term (> 3years) MCAT group.

Economical Assessment of Working Memory and Response Inhibition in ADHD Using a Combined n-back/Nogo Paradigm: An ERP Study

The development of cognitive interventions in attention-deficit/hyperactivity disorder (ADHD) often requires the assessment of multiple cognitive functions. However, experimental settings consisting of various tasks are particularly strenuous for patients and can thus result in poor data quality. For the economical assessment of working memory and response inhibition, this study aims to validate a combined n-back/nogo paradigm by comparing it to single task versions and to demonstrate its applicability for ADHD research. Twenty-five healthy individuals and 34 ADHD patients between 9 and 16 years participated in this event-related potential (ERP) study. Healthy controls underwent single task versions of a 2-back working memory task and a go/nogo response inhibition task as well as the introduced combined 2-back/nogo task. This combined task demonstrated a comparable ERP structure for working memory and response inhibition aspects as single task versions. Behaviorally, higher working memory performance during the combined paradigm indicated lower task difficulty, while high correlations between combined and single task versions still indicated valid working memory measures. For response inhibition performance, different task versions resulted in similar outcomes. The application of the combined n-back/nogo paradigm in ADHD patients revealed the expected working memory and response inhibition deficits, increased omission errors, reaction times, and standard deviation of reaction time, as well as diminished n-back P3 and nogo P3 amplitudes. We conclude that the combined n-back/nogo task is an effective paradigm for the economical assessment of working memory and response inhibition deficits in ADHD on a behavioral and neurophysiological level.

Short-Term Effects of a Passive Spinal Exoskeleton on Functional Performance, Discomfort and User Satisfaction in Patients with Low Back Pain.

Purpose Low back pain (LBP) remains a major worldwide healthcare issue. Recently, spinal exoskeletons were proposed as a potentially useful solution for LBP prevention and vocational reintegration for people who perform heavy load lifting, repetitive movements or work in prolonged static postures. The purpose of this study was to investigate how patients with LBP respond to the novel passive SPEXOR exoskeleton regarding functional performance, discomfort and general user impression. Methods Fourteen patients, with low to moderate LBP (2-7 on a 0-10 scale), performed 12 functional tasks with and without the exoskeleton. In addition to objective performance measures, participants subjectively assessed the level of local low back discomfort, task difficulty and general discomfort on a 0-10 visual analogue scales. Results The SPEXOR exoskeleton had favourable effects on performance and local discomfort during prolonged static forward bending. Minor reductions in performance were observed for sit-stand and ladder climbing tasks. The discomfort associated with the exoskeleton was generally low to moderate (median < 4), except for the 6-min walk test (median = 4.5), which is likely due to the weight of the device and obstruction of upper limb movement. The general impressions were mostly positive, with good adjustability, low interference with the movement and moderate support reported by the participants. Conclusion The SPEXOR exoskeleton is potentially useful for LBP prevention or management, however, further improvements are needed to provide higher levels support during heavy load lifting.

The transition from feature to object: Storage unit in visual working memory depends on task difficulty.

Visual working memory (VWM) is a cognitive memory buffer for temporarily processing and storing visual information. Previous studies suggest that its capacity is severely limited, and there is an ongoing debate on whether the storage capacity is object-based or feature-based in VWM. In this study, a change-detection task was employed to investigate whether and how task difficulty can affect VWM, specifically, its capacity and the unit of storage. Task difficulty was manipulated through the set size of memory items, memory fidelity required by the resolution of representation and the type of feature tested. We examined two types of stimuli: the single-feature type, where each memory item was composed of a single feature (color or shape), and the conjunctive-feature type, where each item was composed of a conjunction of two features (colored shape). Experiment1 replicated the previous findings that memory capacity for colors was larger than shapes, and decreased with the resolution demand regardless of the type of stimuli. In Experiment2, we analyzed and compared the results from single-feature items and conjunctive-feature items in the low- and high-resolution conditions while controlling for the number of to-be-remembered features. By directly matching the estimated capacity based on an object-unit and a feature-unit with the theoretical prediction, the results showed that the unit storage in VWM tended to be feature-based with low task difficulty, and to be object-based with high task difficulty. This suggests that VWM is dynamic and flexible, dependent on the load of the current task.

Observing different model types interspersed with physical practice has no effect on consolidation or motor learning of an elbow flexion–extension task

We compared varied model types and their potential differential effects on learning outcomes and consolidation processes when observational practice was interspersed with physical practice. Participants (N = 75) were randomly assigned to one of five groups: (1) unskilled model observation, (2) skilled model observation, (3) mixed-model observation, (4) physical practice only, and (5) no observational or physical practice (control). All were tasked with learning a waveform-matching task. With exception of the control group not involved in acquisition sessions, participants were involved in one pre-test, two acquisition sessions, four retention tests (immediate-post acquisition 1, 24hr post acquisition 1, immediate-post acquisition 2, and approximate 7-day retention), as well as an approximate 7-day transfer test. No differences were demonstrated in consolidation processes or learning outcomes as all groups showed the same pattern of retention and transfer data. Our conclusion is that motor memory processes were not impacted differentially when different models types were used in observational practice that was intermixed with physical practice for the learning of a movement pattern with low task difficulty, and thus similar learning outcomes emerged for all groups.

Distraction by salient stimuli in adults with attention-deficit/hyperactivity disorder: Evidence for the role of task difficulty in bottom-up and top-down processing

The cognitive mechanisms of increased distractibility in attention-deficit/hyperactivity disorder (ADHD) are poorly understood. The current study investigated the influence of two major modulating factors (emotional saliency, task difficulty) on behavioral and electrophysiological parameters underlying distractibility in ADHD. In addition, the attentional focus (indirect and direct processing of distractors) was examined. Thirty-six adults with ADHD and 37 healthy controls completed two experimental tasks while electroencephalography (EEG) data was collected. Task 1 assessed indirect processing of emotional or neutral distractors during a perceptual judgment task with varying task difficulty. Task 2 measured direct processing of the emotional or neutral stimuli and required participants to rate the stimuli regarding valence and arousal. Results showed that adults with ADHD exhibited generally higher behavioral distractibility than healthy controls. Furthermore, the ADHD group exhibited an enhanced bottom-up processing [increased early posterior negativity (EPN) amplitudes] of distractors in trials with high task difficulty as well as enhanced top-down processing [increased late positive potential (LPP) amplitudes] in trials with low task difficulty. However, no group differences were evident in the neural processing of emotional content or between attentional focus conditions. These findings support the notion that distractibility in ADHD results from impairments to both top-down as well as bottom-up processes and underscore the importance of task difficulty as a modulating factor.

Game-based training of flexibility and attention improves task-switch performance: near and far transfer of cognitive training in an EEG study

There is a demand for ways to enhance cognitive flexibility, as it can be a limiting factor for performance in daily life. Video game training has been linked to advantages in cognitive functioning, raising the question if training with video games can promote cognitive flexibility. In the current study, we investigated if game-based computerized cognitive training (GCCT) could enhance cognitive flexibility in a healthy young adult sample (N = 72), as measured by task-switch performance. Three GCCT schedules were contrasted, which targeted: (1) cognitive flexibility and task switching, (2) attention and working memory, or (3) an active control involving basic math games, in twenty 45-min sessions across 4–6 weeks. Performance on an alternating-runs task-switch paradigm during pretest and posttest sessions indicated greater overall reaction time improvements after both flexibility and attention training as compared to control, although not related to local switch cost. Flexibility training enhanced performance in the presence of distractor-related interference. In contrast, attention training was beneficial when low task difficulty undermined sustained selective attention. Furthermore, flexibility training improved response selection as indicated by a larger N2 amplitude after training as compared to control, and more efficient conflict monitoring as indicated by reduced Nc/CRN and larger Pe amplitude after training. These results provide tentative support for the efficacy of GCCT and suggest that an ideal training might include both task switching and attention components, with maximal task diversity both within and between training games.

Perceptual grouping by similarity of surface roughness in haptics: the influence of task difficulty.

We investigated grouping by similarity of surface roughness in the context of task difficulty. We hypothesized that grouping yields a larger benefit at higher levels of task complexity, because efficient processing is more helpful when more cognitive resources are needed to execute a task. Participants searched for a patch of a different roughness as compared to the distractors in two strips of similar or dissimilar roughness values. We reasoned that if the distractors could be grouped based on similar roughness values, exploration time would be shorter and fewer errors would occur. To manipulate task complexity, we varied task difficulty (high target saliency equalling low task difficulty), and we varied the fingers used to explore the display (two fingers of one hand being more cognitive demanding than two fingers of opposite hands). We found much better performance in the easy condition as compared to the difficult condition (in both error rates and mean search slopes). Moreover, we found a larger effect for the similarity manipulation in the difficult condition as compared to the easy condition. Within the difficult condition, we found a larger effect for the one-hand condition as compared to the two-hand condition. These results show that haptic search is accelerated by the use of grouping by similarity of surface roughness, especially when the task is relatively complex. We conclude that the effect of perceptual grouping is more prominent when more cognitive resources are needed to perform a task.