Higher Levels Of Task Difficulty Research Articles

Cognitive Effort-Based Decision-Making Across Experimental and Daily Life Indices in Younger and Older Adults.

The study investigated whether cognitive effort decision-making measured via a neuroeconomic paradigm that manipulated framing (gain vs. loss outcomes), could predict daily life engagement in mentally demanding activities in both younger and older adults. Younger and older adult participants (N = 310) completed the Cognitive Effort Discounting paradigm (Cog-ED), under both gain and loss conditions, to provide an experimental index of cognitive effort costs for each participant in each framing condition. A subset of participants (N = 230) also completed a 7-day Ecological Momentary Assessment (EMA) protocol measuring engagement in mentally demanding daily life activities. In a large, online sample, we replicated a robust increase in cognitive effort costs among older, relative to younger, adults. Additionally, costs were found to be reduced in the loss relative to gain frame, although these effects were only reliable at high levels of task difficulty and were not moderated by age. Critically, participants who had lower effort costs in the gain frame tended to report engaging in more mentally demanding daily life activities, but the opposite pattern was observed in the loss frame. Further analyses demonstrated the specificity of reward-related cognitive motivation in predicting daily life mentally demanding activities. Together, these results suggest that cognitive effort costs, as measured through behavioral choice patterns in a neuroeconomic decision-making task, can be used to predict and explain engagement in mentally demanding activities during daily life among both older and younger adults.

The CRUNCH model does not account for load-dependent changes in visuospatial working memory in older adults

Numerous neuroimaging studies have shown that older adults tend to activate the brain to a greater extent than younger adults during the performance of a task. This is typically interpreted as evidence for cognitive compensation. The Compensation-Related Utilisation of Neural Circuits Hypothesis (CRUNCH) model is a highly influential model of compensation, and states that increased functional magnetic resonance imaging (fMRI) activity in older adults compared to younger adults should reverse at higher levels of task difficulty. Here, the CRUNCH model was tested using a visuospatial working memory paradigm. fMRI activity in older vs. younger adults was in the opposite direction to that predicted by the model. Given that the CRUNCH model is the predominant model of compensation, this result was surprising. These results were followed up with a systematic review of the CRUNCH in healthy ageing literature. A surprisingly small number of published studies (4) have tested the predictions of the CRUNCH model. Further experimental work is required to validate the CRUNCH model in cognitive ageing.

Learner-Controlled Practice Difficulty and Task Exploration in an Active-Learning Gaming Environment

Background. With the use of computer-based simulations and games becoming increasingly common in education and organizational contexts for delivering training and instruction, learners are being granted unprecedented control over their learning. This increase in learner control leaves large differences in how learners challenge themselves and explore their learning environments. Learners can benefit from task difficulty, an aspect of challenge, when they are neither overwhelmed nor underwhelmed. The purpose of the present lab study was to test a model of how encouraging learners to challenge themselves with greater task difficulty when practicing a video game could be a “double-edged sword” in terms of their skill-based learning. Method. Using a first-person shooter computer game as the criterion task, 120 undergraduate males were randomly assigned to one of two groups. Half of the participants were encouraged to practice at a difficulty level that matched their skill level, while the other half were encouraged to practice at a difficulty that greatly exceeded their skill. Exploratory behavior was reflected in the variety of weapons used. Results. Findings supported a model of inconsistent mediation predicting that difficulty encouragement instructions would lead to higher selected practice difficulty, which in turn would have positive direct effects on skill transfer yet negative indirect effects through exploratory behavior. Discussion. The present study demonstrated that encouraging learners to practice at high levels of task difficulty is a “double-edged sword.” Although high levels of task difficulty can help in the preparation for future difficulties, it can also undermine exploratory behavior which is an important aspect of the learning process. This research speaks to the potential of encouraging learners to practice under difficult conditions without undermining their learning.

Development and validation of a contextual behavioral distress intolerance task in cigarette smokers

IntroductionDistress intolerance, an individual's perceived or actual inability to withstand negative emotional or physical distress, contributes to the maintenance of smoking. However, there is limited understanding of the contextual factors that impact distress intolerance in general or among smokers specifically. This study aimed to adapt and test a computerized behavioral persistence task that requires re-typing a passage while adhering to specific instructions (Contextual-Frustration Intolerance Typing Task [C-FiTT]). C-FiTT was designed to model contextual factors that influence distress intolerance, negative affect, and smoking urges. MethodDaily smokers (n = 550) were recruited through the use of Qualtrics Panels. Using a 2 × 2 + 1 experimental design, participants were randomly assigned to one of four C-FiTT conditions that crossed task difficulty (low or high difficulty) with passage content (neutral or tobacco withdrawal text), or a neutral control group. ResultsC-FiTT produced an average persistence time of 94.1 ± 114.3 s and 64.7% of participants self-terminated the task. C-FiTT also produced small to medium sized-increases in negative affect and smoking urges. Between-condition comparisons indicated that the high-difficulty C-FiTT produced shorter behavioral persistence, greater self-termination likelihood, and larger increases in negative affect and smoking urges. The combination of high-difficulty and withdrawal content resulted in the shortest persistence time, 100% self-termination rate, and largest increases in negative affect and smoking urges, compared to other conditions ConclusionsFindings provide initial evidence for the validity of C-FiTT in smokers within the context of tobacco withdrawal at low and high levels of task difficulty. Avenues for refinement and use of C-FiTT are discussed.

S161. FUNCTIONAL BRAIN NETWORKS INVOLVED IN ATTENTIONAL BIASING IN SCHIZOPHRENIA

BackgroundAlthough the symptomatology in schizophrenia is variable, many of the cognitive deficits that are associated with the illness, including impairments in attention, working memory, verbal learning and executive functions, persist over time from the prodrome to the chronic phase. One of the cognitive domains showing pronounced deficits is executive function, which is the ability to adaptively adjust behavior in the face of changing environmental demands. Attentional biasing is one aspect of executive function that attentuates conflict between competing stimuli (or competing features of a stimulus) via the top-down regulation of attention. The goal of this study was to use functional magnetic resonance imaging (fMRI) to isolate the brain activity related to differences in levels of attentional biasing in schizophrenia patients, where these levels were varied from trial-to-trial by manipulating the number of relevant stimulus dimensions.MethodsParticipants - Twenty-three schizophrenia patients and twenty-one healthy volunteers, matched on age and gender, were recruited from the Vancouver area.Task – The task involved performing three discrete tasks in alternation: judging whether shapes are blue or red, judging whether numbers are odd or even, and judging whether letters are uppercase or lowercase. Each stimulus contained either one dimension that cued a task in the task set (e.g. the numeral ‘2’ in white ink), two dimensions (e.g. the numeral ‘2’ in blue ink), or three dimensions, such that all three tasks in the set are cued (e.g. the word ‘TWO’ written in blue ink). Each stimulus was presented in the center of the screen and the judgment to be performed was cued with a single word followed by a question mark.ResultsThe fMRI data was analyzed using Constrained Principal Component Analysis, which identifies brain networks common to all participants and indexes the activity of each network for each participant. Three components were extracted for further examination.Component 1 displayed activations located in the visual cortices, parietal lobes, primary motor areas, supplementary motor area (SMA), dorsal anterior cingulate cortex (dAcc), and cerebellum. The statistical analysis indicated that this component was reliable but did not differentiate between patients and volunteers.Component 2 displayed activations in the occipital lobes, dAcc, SMA, parietal lobes and primary motor areas, and deactivations in the medial prefrontal cortices and the posterior cingulate/precuneus. The statistical analysis indicated that the activity in this component was reliable, and became stronger as stimulus dimensions increased. However, the patients did not increase activity to the same degree as the volunteers in the most challenging condition.Component 3 displayed activations in the occipital lobes, hippocampi, and left parietal and primary motor areas as well as deactivations in superior and middle frontal gyri. The statistical analysis indicated that this component was reliable, but activity levels did not differentiate between patients and volunteers.DiscussionThe results indicate that patients and volunteers activated the same networks while performing the attentional biasing task. However, the statistical analysis of Component 2 suggests that patients display an inefficient pattern of brain activity, such that they have higher levels of activity than volunteers when little attentional biasing is required and significantly lower levels of activity than volunteers when high levels of attentional biasing was required. This pattern of results is suggestive of inefficient neural activity, particularly at higher levels of task difficulty, a finding which has previously been described in the schizophrenia literature.

Do complaints of everyday cognitive failures in high schizotypy relate to emotional working memory deficits in the lab?

BackgroundIndividuals high on schizotypy complain of increased cognitive failures in everyday life. However, the neuropsychological performance of this group does not consistently indicate underlying ability deficits. It is possible that current neuropsychological tests lack ecological validity. Given the increased affective reactivity of high schizotypes, they may be more sensitive to emotional content interfering with cognitive ability. This study sought to explore whether an affective n-back working memory task would elicit impaired performance in schizotypy, echoing complaints concerning real world cognition. Methods127 healthy participants completed self-report measures of schizotypy and cognitive failures and an affective n-back working memory task. This task was varied across three levels of load (1- to 3-back) and four types of stimulus emotion (neutral, fearful, happy, sad). Differences between high (n=39) and low (n=48) schizotypy groups on performance outcomes of hits and false alarms were examined, with emotion and load as within-groups variables. ResultsAs expected, high schizotypes reported heightened vulnerability to cognitive failures. They also demonstrated a relative working memory impairment for emotional versus neutral stimuli, whereas low schizotypes did not. High schizotypes performed most poorly in response to fearful stimuli. For false alarms, there was an interaction between schizotypy, load, and emotion, such that high schizotypy was associated with deficits in response to fearful stimuli only at higher levels of task difficulty. Inclusion of self-reported cognitive failures did not account for this. ConclusionThese findings suggest that the “gap” between subjective and objective cognition in schizotypy may reflect the heightened emotional demands associated with cognitive functioning in the real world, although other factors also seem to play a role. There is a need to improve the ecological validity of objective assessments, whilst also recognizing that self-reported cognitive failures tap into a range of factors difficult to assess in the lab, including emotion. Cognitive interventions for at-risk individuals will likely be more beneficial if they address emotional processing alongside other aspects of cognition.

Comparative Effects of Different Balance-Training-Progression Styles on Postural Control and Ankle Force Production: A Randomized Controlled Trial.

Despite the effectiveness of balance training, the exact parameters needed to maximize the benefits of such programs remain unknown. One such factor is how individuals should progress to higher levels of task difficulty within a balance-training program. Yet no investigators have directly compared different balance-training-progression styles. To compare an error-based progression (ie, advance when proficient at a task) with a repetition-based progression (ie, advance after a set amount of repetitions) style during a balance-training program in healthy individuals. Randomized controlled trial. Research laboratory. A total of 28 (16 women, 12 men) physically healthy young adults (age = 21.57 ± 3.95 years, height = 171.60 ± 11.03 cm, weight = 72.96 ± 16.18 kg, body mass index = 24.53 ± 3.7). All participants completed 12 supervised balance-training sessions over 4 weeks. Each session consisted of a combination of dynamic unstable-surface tasks that incorporated a BOSU ball and lasted about 30 minutes. Static balance from an instrumented force plate, dynamic balance as measured via the Star Excursion Balance Test, and ankle force production in all 4 cardinal planes of motion as measured with a handheld dynamometer before and after the intervention. Selected static postural-control outcomes, dynamic postural control, and ankle force production in all planes of motion improved (P < .05). However, no differences between the progression styles were observed (P > .05) for any of the outcome measures. A 4-week balance-training program consisting of dynamic unstable-surface exercises on a BOSU ball improved dynamic postural control and ankle force production in healthy young adults. These results suggest that an error-based balance-training program is comparable with but not superior to a repetition-based balance-training program in improving postural control and ankle force production in healthy young adults.

A ‘HEART OF GOAL’ AND THE WILL TO SUCCEED: GOAL COMMITMENT AND TASK PERFORMANCE AMONG TEACHERS IN PUBLIC SCHOOLS

Much research suggests that employee goal commitment is predictive of work behaviour and performance. However, public administration research has yet to establish the linkage between goal commitment and task performance in the context of public service employees. Using survey data on school teachers with administrative data on students, this article employs within‐student between‐teachers fixed effects and shows how teachers' goal commitment affects their task performance. Moreover, the article shows how task difficulty moderates this relationship. The findings suggest that higher goal commitment promotes teacher task performance, in particular, at moderate to high levels of task difficulty.

Does conflict help or hurt cognitive control? Initial evidence for an inverted U-shape relationship between perceived task difficulty and conflict adaptation

Sequential modulation of congruency effects in conflict tasks indicates that cognitive control quickly adapts to changing task demands. We investigated in four experiments how this behavioral congruency-sequence effect relates to different levels of perceived task difficulty in a flanker and a Stroop task. In addition, online measures of pupil diameter were used as a physiological index of effort mobilization. Consistent with motivational accounts predicting that increased levels of perceived task difficulty will increase effort mobilization only up to a certain limit, reliable dynamic conflict-driven adjustment in cognitive control was only observed when task difficulty was relatively low. Instead, tasks tentatively associated with high levels of difficulty showed no or reversed conflict adaptation. Although the effects could not be linked consistently to effects in self-reported task difficulty in all experiments, regression analyses showed associations between perceived task difficulty and conflict adaptation in some of the experiments, which provides some initial evidence for an inverted U-shape relationship between perceived difficulty and adaptations in cognitive control. Furthermore, high levels of task difficulty were associated with a conflict-driven reduction in pupil dilation, suggesting that pupil dilation can be used as a physiological marker of mental overload. Our findings underscore the importance of developing models that are grounded in motivational accounts of cognitive control.

Age and task difficulty differences in dual tasking using circle tracing and serial subtraction tasks

The aim of this study was to investigate age-related differences in dual task performance by using an upper limb proprioceptive task. Twenty-eight younger (18-30years) and 28 older (>60years) healthy adults performed circle tracing and serial subtraction tasks separately and concurrently. The tasks had two levels of difficulty: easy and hard. The circle tracing task included direct (easy) and indirect (hard) visual feedback conditions, and it was paired with serial subtraction by twos (easy) or threes (hard). We found that older adults were significantly slower than younger adults across all conditions and had significantly greater dual task costs when they performed circle tracing with easy serial subtraction. Higher levels of task difficulty were associated with slower speed in both groups. We found no age differences in accuracy. Participants either traded speed for accuracy or accuracy for speed regardless of age group. Overall, the findings suggest that speed and accuracy may be affected differently during dual tasking. In addition, older adults may rely more extensively on proprioceptive feedback to guide upper limb movement compared with younger adults.

The impact of age and motivation on cognitive effort: Implications for cognitive engagement in older adulthood.

We examined age differences in the effort required to perform the basic cognitive operations needed to achieve a specified objective outcome, and how hypothesized increases in effort requirements in later life are related to intrinsic motivation associated with enjoyment of and participation in effortful cognitive activities. Young (N = 59; 20-40 years) and older (N = 57; 64-85 years) adults performed a memory-search task varying in difficulty across trials, with systolic blood pressure responsivity-calculated as the increase over baseline during task performance-used as a measure of effort expenditure and task engagement. Consistent with expectations, older adults exhibited greater levels of responsivity (i.e., effort) at all levels of objective task difficulty, and this increase was reflected in subjective perceptions of difficulty. Older adults also exhibited greater levels of disengagement (i.e., effort withdrawal) than younger adults at higher levels of task difficulty, conceivably reflecting the disproportionately greater effort required for successful performance in the former group. We also found that, relative to younger adults, older adults' engagement was more sensitive to the importance attached to the task (i.e., motivation to do well). Finally, we also obtained evidence that increased costs associated with cognitive engagement in later life were negatively associated with intrinsic levels of motivation to engage in effortful cognitive activity. The results support the general conclusion that the costs of cognitive activity increase with age in adulthood, and that these costs influence individuals' willingness to engage resources in support of demanding cognitive activities.

Theta frequency band activity and attentional mechanisms in visual and proprioceptive demand

In a companion manuscript we reported reduced electroencephalographic (EEG) activation at traditional sensorimotor areas in knee movements with high levels of task difficulty modulated by varying visual and proprioceptive sensory demands. Given that reduced cortical activity with more complex tasks is counter-intuitive, we suggested that high order cognitive-motor areas may show increased EEG activation to compensate for the observed decrease in sensorimotor regions. To test this hypothesis, we evaluated theta band activation at anterior frontal regions in a secondary analysis of our previous data. Unlike activation at sensorimotor areas, anterior frontal responses increased with each level of task difficulty as modulated by precision of visual targeting and/or proprioceptive demands from adding masses to the leg. Activity was increased as both unimodal visual and proprioceptive requirements became more demanding, but showed greater sensitivity to visual over proprioceptive processing requirements. Each level of bimodal task demands showed increasing activation, which was consistently greater when modulated through visual demands. These results are consistent with our hypothesis of increased contribution of anterior frontal regions for motor control in lower extremity movements with increasing sensory demands and further support different mechanisms for internally and externally guided movement.

Effects of the α4β2 Partial Agonist Varenicline on Brain Activity and Working Memory in Abstinent Smokers

Cognitive alterations are a core symptom of nicotine withdrawal, contributing to smoking relapse. In rodents and humans, cognitive deficits can be reversed by treatment with the alpha4beta2 nicotinic receptor partial agonist varenicline. This neuroimaging study examined the neural mechanisms that underlie these effects. Twenty-two smokers completed 13 days of varenicline and placebo treatment in a double-blind crossover study with two functional magnetic resonance imaging sessions: after 3 days of abstinence while on varenicline and after 3 days of abstinence while on placebo (counterbalanced randomized order, 2-week washout). Blood oxygenation level-dependent (BOLD) data were acquired during performance of a visual N-back working memory task. In a region of interest analysis, significant effects of treatment on mean percent signal change (varenicline > placebo) were observed in the dorsal anterior cingulate/medial frontal cortex, left dorsolateral prefrontal cortex, and right dorsolateral prefrontal cortex. In a cross-region model, there was a significant interaction of treatment by memory load, indicating significant increases in BOLD signal for varenicline versus placebo at the 2-back and 3-back levels but not the 1-back level. Varenicline improved performance (correct response time) in highly dependent smokers with no effect among less dependent smokers. In highly dependent smokers, faster correct response time was associated with increased BOLD signal. This study provides novel evidence that the alpha4beta2 partial agonist varenicline increases working memory-related brain activity after 3 days of nicotine abstinence, particularly at high levels of task difficulty, with associated improvements in cognitive performance among highly dependent smokers.

Non-linear gaining in precision aiming: Making Fitts’ task a bit easier

The role of information in the processes underlying kinematic trajectory-formation was examined by manipulating the relation between effector space (movement of a hand-held stylus on a graphics tablet) and task space (movement of a cursor on a screen where targets were presented) in a precision aiming task with five different levels of task difficulty. Movement patterns were found to evolve as a function of the flow of information in task space, with participants (N=13) producing more rapid and more fluent movements when the mapping between spaces included the softening-spring characteristics typical of behavioural patterns at higher levels of task difficulty. We conclude that the kinematic changes (movement time and pattern) observed when task difficulty increases result from informational influences. Information affects behavioural dynamics at the level of the parameters without affecting the underlying dynamical structure.

Feedforward and feedback processes in motor control

In this study, we utilized functional magnetic resonance imaging (fMRI) to examine which brain regions contribute to feedback and feedforward motor control processes. Several studies have investigated the contributions of cortical and subcortical brain regions to motor performance by independently varying factors such as movement rate, force, and speed, and observing the neural responses. Such studies have contributed greatly to our understanding of neural coding of movement variables. Under natural movement conditions, however, these factors interact in a complex manner to produce differing performance levels. In the current investigation, we induced performance changes in a less constrained way, by having subjects move a joystick to hit targets of differing sizes on an LCD screen. These parametric changes in target size resulted in the well-known speed–accuracy tradeoff effect, allowing us to examine the brain regions responsive to global shifts in motor performance levels. That is, movements made to larger targets relied more on feedforward control whereas movements made to smaller targets relied more on feedback control. Using functional MRI, we identified two sets of brain regions in which activation was modulated with task difficulty. Areas exhibiting activation that was positively correlated with increasing target size included primary motor cortex, premotor cortex, and the basal ganglia, regions that are typically classified as playing a role in force control and movement planning. Brain regions whose activation was negatively correlated with increasing target size included the ipsilateral sensorimotor cortex, multiple cerebellar regions, and the thalamus. These areas contributed to motor performance under higher levels of task difficulty. The results elucidate cortical and subcortical brain regions that are responsive to global shifts in motor performance, reflecting changes along the continuum of feedforward and feedback motor control.

Informational constraints in human precision aiming

Twelve human subjects performed a reciprocal precision aiming task of varying difficulty (index of difficulty=4, 5, or 6) while vision of the ongoing movement was available either continuously or intermittently. In the intermittent conditions, vision of the moving end-effector was available at regular intervals (equal to 100%, 125%, or 150% of the movement durations measured under continuous visibility conditions) for varying amounts of time (75%, 50%, or 25% of the duration of the interval). Movement time (MT) increased with both increasing task difficulty and decreasing availability of visual information. Increases in MT were brought about by the same systematic changes in the kinematic characteristics of movement, whether task difficulty increased or availability of visual information decreased. At higher levels of task difficulty, subjects organized their movements so as to make visual information available at particular instances (at the start and at the end of the aiming movement).

Individual Versus Group Decision Making: Social Comparison in Goals for Individual Task Performance

This experiment compares the decisions of individuals and groups on goals for the performance expected from individuals on a problem‐solving or an error‐checking task. For both tasks, two versions were constructed to reflect low and high levels of task difficulty. Predictions from two different social comparison of abilities approaches were formulated, with the social comparison based on success approach predicting that group goals would be easier than individual goals, while social comparison based on performance predicted the opposite pattern. Consistent with the social comparison based on success predictions, group goals were observed to be significantly less difficult than individual goals for both tasks, both levels of task difficulty, and for both an initial and a second goal‐setting occasion. Of particular interest was a finding that the easier group goals reflected group member preferences for easy goals in anticipation of group decision making. It is proposed that social factors such as evaluation apprehension and social comparison may be responsible for the differences observed in group and individual goal decisions, and that social factors may have an important role in a variety of goal‐setting situations.

Neuropsychological deficits and CT scan changes in elderly depressives

A number of computerized tests were used to study visual attention, memory and learning in elderly depressed patients. Impairment was found in approximately 70% of depressed patients and was seen particularly in memory and in measures of latency. Depressed patients showed equivalent impairment in short-term memory but less impairment in conditional associative learning compared to a group of patients with early dementia of the Alzheimer-type (DAT), matched for age and pre-morbid IQ. With respect to qualitative differences between depression and DAT, depressed patients showed a different pattern of errors and a consistently prolonged latency of response which was independent of delay in a delayed matching-to-sample test. On recovery from depression, although improvement was seen in most test scores, performance in measures of latency and in a number of tests of memory and learning failed to reach the level seen in a group of matched control subjects and approximately 35% of patients continued to show impairment. For the depressed patients, ventricular brain ratio (VBR) correlated with measures of slowing. In addition, in the 'recovered-depressives', VBR correlated with poor performance at high levels of task difficulty. These findings are discussed with respect to previous literature on the pattern of cognitive impairment and CT scan findings in depression.

Simple and choice reaction time in patients with human immunodeficiency virus infection

The performance of 56 homosexual men infected with human immunodeficiency virus (HIV) was compared to that of 23 HIV antibody-seronegative controls on simple (SRT) and choice (CRT) reaction time tasks. Patients were classified into 3 groups according to Centers for Disease Control clinical criteria. There were 18 patients who had acquired immunodeficiency syndrome (AIDS), 18 who had AIDS-related complex (ARC), and 20 who were HIV antibody-seropositive but otherwise asymptomatic (HIV-Ab+). The SRT task consisted of 5 trials, each containing 10 target stimuli. The CRT task consisted of 10 trials, each containing 5 target stimuli randomly interspersed with 5 nontarget stimuli. The mean response latency of each of the patient groups on the SRT task was not significantly different from that of controls. However, the performance of patients with AIDS or ARC on the CRT task was significantly lower than that of controls, whereas that of HIV-Ab+ patients was not. Analysis of the quality of RT task performance also indicated that the impairment of processing efficiency at higher levels of task difficulty reflected a disruption of processing prior to the response selection stage.

Handedness classification: preference versus proficiency.

Relative hand preferences as indicated by questionnaire were compared with asymmetries in manual proficiency at three levels of task difficulty (N equal to 63 adults). Correlations between odd/even trial relative hand proficiency scores were .887 and .879 attesting to their stability. Test-retest (6-wk. interval) reliabilities for relative hand proficiency ranged from .831 to .893. Spearman rbos between the questionnaire responses and relative hand proficiency were .733, .689, and .619. These relatively low relationships, especially at the highest level of task difficulty (r2 = 38%), indicate that hand preference does not reflect relative hand proficiency at moderate to high levels of task difficulty.