Measurement of functional task difficulty during motor learning: What level of difficulty corresponds to the optimal challenge point?

The relationship between task difficulty and learning benefit was examined, as was the measurability of task difficulty. Participants were required to learn a postural control task on an unstable surface at one of four different task difficulty levels. Results from the retention test showed an inverted-U relationship between task difficulty during acquisition and motor learning. The second-highest level of task difficulty was the most effective for motor learning, while learning was delayed at the most and least difficult levels. Additionally, the results indicate that salivary α-amylase and the performance dimension of the National Aeronautics and Space Administration-Task Load Index (NASA-TLX) are useful indices of task difficulty. Our findings suggested that instructors may be able to adjust task difficulty based on salivary α-amylase and the performance dimension of the NASA-TLX to enhance learning.     

Measurement of auditory cues in drivers' distraction

A driving simulator was used to examine the effects on driving performance of auditory cues in an in-vehicle information search task. Drivers' distraction by the search tasks was measured on a peripheral detection task. The difficulty of the search task was systematically varied to test the distraction caused by a quantified visual load. 58 participants completed the task. Performance on both search tasks and peripheral detection tasks was measured by mean response time and percent error. Analyses indicated that in-vehicle information search performance can be severely degraded when a target is located within a group of diverse distractors. Inclusion of an auditory cue in the visual search increased the mean response time as a result of a change in modality from auditory to visual. Inclusion of such an auditory cue seemed to influence distraction as measured by performance on the peripheral detection task; accuracy was lower when auditory cues were provided, and responses were slower when no auditory cues were provided. Distraction by the auditory cue varied according to the difficulty of the search task.     

Children's search behaviour in large-scale space: developmental components of exploration

It has been argued that visual-search tasks provide a valid model for foraging behaviour. However, Gilchrist et al (2001 Perception 30 1459-1464) demonstrated that, whilst some aspects of behaviour transferred to large-scale egocentric search, there were substantially fewer revisits to previously searched locations than would be expected from the visual-search literature. This difference might be a result of the greater effort required to search in a large-scale egocentric context. Here, we present a novel, automated paradigm, for examining the effect of effort on egocentric search behaviour by manipulating the motor difficulty of the task. Children searched for a hidden target amongst a randomised display of lights by activating a switch at each potential location. The motor difficulty of the task was manipulated by requiring children to search with either their dominant or their nondominant hand. We found that when children searched with their nondominant hand, they made significantly more revisits to previously checked locations than they did when using their dominant hand. This suggests that, when the motor response was more effortful, children were less able to efficiently guide their search behaviour. Individuals with a greater visuo-spatial short-term memory span performed the task more quickly than those with a lower span. However, search latencies were unrelated to general fluid intelligence. This highlights the role of spatial working memory in the development of efficient exploration of large-scale space.     

The Effects of Attentional Focus Instructions and Task Difficulty in a Paced Fine Motor Skill

Abstract

An external focus of attention is considered superior to an internal focus for learning and performance. However, findings specific to changing the task difficulty are inconsistent. The present study used a reciprocal aiming task to determine the effects of attentional focus on motor performance using speed-accuracy paradigm. We constrained timing to examine how internal and external focus of attention influenced accuracy when task difficulty changes. The results indicated greater accuracy on the right target and greater consistency on both targets for the external focus condition, regardless of task difficulty. Our results uniquely demonstrated how instruction modified a speed-accuracy task.     

A test of engagement versus disengagement in catastrophe models

The present study explored the interactive effects of self‐efficacy and increasing/decreasing task difficulty upon engagement and disengagement within a cusp‐catastrophe model framework. Using a closed motor skill aiming task participants (N=60) were required to compete in conditions where task difficulty increased and then decreased (or vice versa) where they were rewarded for good performance but penalized for bad. Participants who reported low levels of self‐efficacy disengage at an earlier level of task difficulty than their high self‐efficacy counterparts. Furthermore, this group did not re‐engage with the task until task difficulty had significantly decreased. Although task disengagement occurred with high difficulty in the high self‐efficacy group, this group re‐engaged in a similar manner in which they disengaged. Findings support and extend those of previous tests of catastrophe models by directly allowing for task disengagement.     

任务难度对自闭症儿童视觉搜索优势显现的影响

探究自闭症谱系障碍(ASD)儿童视觉搜索优势的显现是否受任务难度影响及优势存在机理。本研究采集ASD和正常发育(TD)儿童完成不同难度等级视觉搜索任务的行为和眼动数据。结果发现：在高难度等级任务中ASD组的准确率显著高于TD组;ASD组在任务中对目标刺激的回视次数、对靶子和外周感兴趣区的注视时间显著少于TD组,且ASD组偏好注视刺激的右侧区域。结果表明ASD儿童视觉搜索优势显现受任务难度影响,且可能与其对干扰刺激增强的知觉能力有关。     

The relationship between task difficulty and motor performance complexity

Difficult tasks are commonly equated with complex tasks across many behaviors. Motor task difficulty is traditionally defined via Fitts’ law, using evaluation criteria based on spatial movement constraints. Complexity of data is typically evaluated using non-linear computational approaches. In this project, we investigate the potential to evaluate task difficulty via behavioral (motor performance) complexity in a Fitts-type task. Use of non-linear approaches allows for inclusion of many features of motor actions that are not currently included in the Fitts-type paradigm. Our results indicate that tasks defined as more difficult (using Fitts movement IDs) are not associated with complex motor behaviors; rather, an inverse relationship exists between these two concepts. Use of non-linear techniques allowed for the detection of behavioral differences in motor performance over the entire action trajectory in the presence of action errors and among neutrally co-constrained effectors not detected using traditional Fitts’-type analyses utilizing movement time measures. Our findings indicate that task difficulty may potentially be inferred using non-linear measures, particularly in ecological situations that do not obey the Fitts-type testing paradigm. While we are optimistic regarding these initial findings, further work is needed to assess the full potential of the approach.     

Unique behavioral strategies in visuomotor learning: Hope for the non-learner

The existence of individual differences in motor learning capability is well known but the behaviors or strategies that contribute to this variability have been vastly understudied. What performance characteristics distinguish an expert level performer from individuals who experience little to no success, those labeled non-learners? We designed a rule-based visuomotor task which requires identification (discovery) and then exploitation of specific explicit and implicit task components that requires a specific movement pattern, the task rule, for goal achievement. When participants first attempt the task, they are informed about the goal, but are naïve to the task rule. Therefore, the purpose of this experiment is to determine how acquisition of both implicit and explicit task components, the inherent elements of the task rule, reveals differing strategies associated with performance and task success. We test the hypothesis that an examination of performance will reveal sub-groups with varying levels of success. Further, for each subgroup, we expect to find a unique relationship between visual Time-in-Target feedback (a measure of success) and subsequent updating of each task component. Out of 32 non-disabled adults, we identified three distinct sub-groups: (Low Performer/Non-Learner (LP, N = 9), Moderate Performer (MP, N = 12) and High Performer (HP, N = 11)). A quantitative analysis of behavioral patterns reveals three findings: First, the LP sub-group demonstrated significantly lower task success which was associated with difficulty identifying the explicit component of the task. Second, the HP sub-group acquired the two task components in parallel over practice. Third, when both explicit and implicit component performance is plotted across sub-groups, a task component continuum emerges that seamlessly progresses from low to moderate to high performer groups. An exploratory analysis reveals that self-reported level of prior lifetime accumulation of video game and physical activity experience is a significant predictor of individual task performance (R² = 0.50). In summary, what appears to be a key distinction between varying levels of human rule-based motor learning is the process by which feedback is used to update performance of inherent elements of the task rule. Evidence of a performance continuum and limited prior experience suggests that Low Performer/Non-Learners are generally inexperienced with these kinds of tasks, although the role of genetics and other innate learning capabilities in visuomotor learning is still largely unknown. These findings provoke new research directions toward probing the differential performance strategies associated with expertise and the development of interventions aimed to convert non-learners into learners.     

Motor Behavior Concepts in the Study of Balance: A Scoping Review

Abstract

Previous research suggests that using Fitts’ law; attentional focus or challenge point framework (CPF) is beneficial in balance control studies. A scoping review was conducted to examine studies that utilized these motor behavior concepts during balance control tasks. An extensive literature search was performed up to January 2018. Two independent reviewers conducted a study selection process followed by data extraction of the search results. Forty-six studies were identified, with 2 studies related to CPF, 12 studies related to Fitts’ law and 32 studies related to focus of attention. The CPF appears to be a useful method for designing a progressive therapeutic program. Fitts’ law can be used as a tool for controlling the difficulty of motor tasks. Focus of attention studies indicate that adopting an external focus of attention improves task performance. Overall, studies included in this review report benefit when using the selected motor behavior concepts. However, the majority (>80%) of studies included in the review involved healthy populations, with only three clinical trials. In order to ascertain the benefits of the selected motor behavior concepts in clinical settings, future research should focus on using these concepts for clinical trials to examine balance control among people with balance impairments.     

Mediating factors in the arousal-performance relationship

The arousal-performance relationship was investigated within a social facilitation experiment, in which two major task dimensions (cognitive-motor and difficulty) were manipulated and two arousal measures (palmar sweat and self-reports) were taken. Subjects (75 male and 75 female introductory psychology students) were randomly assigned to one of five audience conditions and one of three task difficulty levels. Each subject performed three tasks, which varied as to cognitive and motor requirements, under a uniform difficulty level. No significant differences were found on any arousal or performance measure due to the audience manipulation. Females were found to be more aroused by the audiences than males, on both arousal measures. When self-reported arousal scores were quintiled to create five post hoc arousal conditions, significant interactions between these conditions and task difficulty level were obtained for both the cognitive and motor tasks. (No significant differences were found using quintiled palmar sweat scores.) On the basis of the similar pattern of these interactions, it was concluded that the inverted-U function was obtained only on high-difficulty tasks.     

The influence of motor function on processing speed in preterm and term-born children

This study investigates the relationship between motor function and processing speed in preterm children. Processing speed was compared in 145 adolescents, born 25–41 weeks gestational age, utilizing tasks including differing motor demands. The influence of motor cortex excitability and functional motor skills on task performance was assessed. For tasks with motoric demands, differences in performance between preterm and term-born children were mediated by the relationship between gestational age, corticomotor excitability, and motor function. There were no differences in non-motor processing speed task performance between preterm and term-born children. Measures of processing speed may be confounded by a timed motor component.     

Investigating the visual span in comparative search: the effects of task difficulty and divided attention

In three experiments, participants' visual span was measured in a comparative visual search task in which they had to detect a local match or mismatch between two displays presented side by side. Experiment 1 manipulated the difficulty of the comparative visual search task by contrasting a mismatch detection task with a substantially more difficult match detection task. In Experiment 2, participants were tested in a single-task condition involving only the visual task and a dual-task condition in which they concurrently performed an auditory task. Finally, in Experiment 3, participants performed two dual-task conditions, which differed in the difficulty of the concurrent auditory task. Both the comparative search task difficulty (Experiment 1) and the divided attention manipulation (Experiments 2 and 3) produced strong effects on visual span size.     

The development of organized visual search

Visual search plays an important role in guiding behavior. Children have more difficulty performing conjunction search tasks than adults. The present research evaluates whether developmental differences in children's ability to organize serial visual search (i.e., search organization skills) contribute to performance limitations in a typical conjunction search task. We evaluated 134 children between the ages of 2 and 17 on separate tasks measuring search for targets defined by a conjunction of features or by distinct features. Our results demonstrated that children organize their visual search better as they get older. As children's skills at organizing visual search improve they become more accurate at locating targets with conjunction of features amongst distractors, but not for targets with distinct features. Developmental limitations in children's abilities to organize their visual search of the environment are an important component of poor conjunction search in young children. In addition, our findings provide preliminary evidence that, like other visuospatial tasks, exposure to reading may influence children's spatial orientation to the visual environment when performing a visual search.     

Pain and athletes: Contact sport participation and performance in pain

ObjectivesThis study examined the effect of cold pressor pain on performance in high-contact athletes, low-contact athletes and non-athletes.DesignA three-group between-subjects experimental design was used.MethodSeventy-one participants completed a motor task and a cognitive task of different complexity (easy or hard) both in pain and not in pain. The motor task involved participants throwing a tennis ball at numbered targets in the correct order. In the cognitive task, participants were required to check off the numbers one to twenty-five in the correct order from a grid of randomly ordered numbers. Task difficulty was increased by adding dummy targets (motor task) or extra numbers (cognitive task).ResultsCold pressor pain was rated as less intense by high-contact athletes during both tasks compared to low-contact athletes and non-athletes. High-contact athletes’ performance was not hampered by pain on the motor task, whereas it was in low-contact athletes and non-athletes. However, pain did not hamper performance for any group during the cognitive task. Low-contact and non-athletes did not differ from each other in their pain reports or the degree to which their performance was hampered by pain in either task.ConclusionsThis study provides evidence that adaptation to pain through participation in high-contact sports can enhance both pain tolerance generally and motor performance specifically under increases in pain. The mechanisms behind these differences warrant further exploration.     

Effort during visual search and counting: insights from pupillometry

We investigated the processing effort during visual search and counting tasks using a pupil dilation measure. Search difficulty was manipulated by varying the number of distractors as well as the heterogeneity of the distractors. More difficult visual search resulted in more pupil dilation than did less difficult search. These results confirm a link between effort and increased pupil dilation. The pupil dilated more during the counting task than during target-absent search, even though the displays were identical, and the two tasks were matched for reaction time. The moment-to-moment dilation pattern during search suggests little effort in the early stages, but increasingly more effort towards response, whereas the counting task involved an increased initial effort, which was sustained throughout the trial. These patterns can be interpreted in terms of the differential memory load for item locations in each task. In an additional experiment, increasing the spatial memory requirements of the search evoked a corresponding increase in pupil dilation.These results support the view that search tasks involve some, but limited, memory for item locations, and the effort associated with this memory load increases during the trials. In contrast, counting involves a heavy locational memory component from the start.     

Age differences between children and young adults in the dynamics of dual-task prioritization: body (balance) versus mind (memory)

Task prioritization can lead to trade-off patterns in dual-task situations. The authors compared dual-task performances in 9- and 11-year-old children and young adults performing a cognitive task and a motor task concurrently. The motor task required balancing on an ankle-disc board. Two cognitive tasks measured working memory and episodic memory at difficulty levels individually adjusted during the course of extensive training. Adults showed performance decrements in both task domains under dual-task conditions. In contrast, children showed decrements only in the cognitive tasks but actually swayed less under dual-task than under single-task conditions and continued to reduce their body sway even when instructed to focus on the cognitive task. The authors argue that children perform closer to their stability boundaries in the balance task and therefore prioritize protection of their balance under dual-task conditions.     

Search Strategies in Practice: Testing the Effect of Inherent Variability on Search Patterns

Abstract

To execute a motor solution to a given task, individuals search through the space of movement possibilities guided by information that arises from the interaction with task and environment. Through this search, individuals seek to avoid inappropriate solutions through local minima in the task space. The processes that lead to some but not all individuals avoiding local minima and finding solutions is not yet understood. Based on the tenets of ecological psychology for perception and action, we examined in two experiments the hypothesis that the incapacity to differentiate errors (performance of an inappropriate solution) from inherent variability would interfere with the perception of properties of the task space and result in a longer time performing an inappropriate solution for the task before exploration of other solutions. Inherent variability was shown to be a direct predictor of the changes in the search strategies. Also, we found that the specifics of the search patterns could predict the performance in the task. Thus, the pattern of motion through the task space affords perception of specific properties of this space guiding individuals in the evolving dynamics of exploration or exploitation.     

Effort during visual search and counting: Insights from pupillometry

We investigated the processing effort during visual search and counting tasks using a pupil dilation measure. Search difficulty was manipulated by varying the number of distractors as well as the heterogeneity of the distractors. More difficult visual search resulted in more pupil dilation than did less difficult search. These results confirm a link between effort and increased pupil dilation. The pupil dilated more during the counting task than during target-absent search, even though the displays were identical, and the two tasks were matched for reaction time. The moment-to-moment dilation pattern during search suggests little effort in the early stages, but increasingly more effort towards response, whereas the counting task involved an increased initial effort, which was sustained throughout the trial. These patterns can be interpreted in terms of the differential memory load for item locations in each task. In an additional experiment, increasing the spatial memory requirements of the search evoked a corresponding increase in pupil dilation.These results support the view that search tasks involve some, but limited, memory for item locations, and the effort associated with this memory load increases during the trials. In contrast, counting involves a heavy locational memory component from the start.     

Metacognitive components of visual search in children

Two studies examined children's increasing ability to analyze tasks in terms of the perceptual features that affect task difficulty. Of particular interest was any understanding that perceptual confusions occur during the search for an object surrounded by objects similar in shape or color to that object. In Study 1, 32 pre-schoolers constructed arrays intended to make the search easy or difficult. They made the search difficult simply by putting many toys into the toy box. In a forced-choice situation, they indicated that task difficulty was influenced by the number of objects and the similarity in color and shape of the targets and the surrounding objects. Study 2 more thoroughly examined knowledge of color and shape confusions, using 96 children from Grades K, 1, 3, and 4, assigned to two age groups. The older children but not the younger ones showed a significant understanding of color and shape confusions. Both age groups understood that performance is affected by a person's interest level and degree of attention to the task. The results were discussed in terms of the accessibility of the children's knowledge under different conditions.     

Challenge Point: A Framework for Conceptualizing the Effects of Various Practice Conditions in Motor Learning

The authors describe the effects of practice conditions in motor learning (e.g., contextual interference, knowledge of results) within the constraints of 2 experimental variables: skill level and task difficulty. They use a research framework to conceptualize the interaction of those variables on the basis of concepts from information theory and information processing. The fundamental idea is that motor tasks represent different challenges for performers of different abilities. The authors propose that learning is related to the information arising from performance, which should be optimized along functions relating the difficulty of the task to the skill level of the performer. Specific testable hypotheses arising from the framework are also described.