The role of task difficulty in the control of dynamic balance in children and adults

Although several studies have explored the development of balance control in children, few have addressed the influence of task difficulty on balance control under dynamic and ecologically valid conditions. In this study, reaching tasks in three directions to two distances enabled the examination of balance control in the context of graded task difficulty. Balance control was measured in younger (6 years) and older (10-11 years) children and adults using center of pressure (COP) measures (initial position, excursion, and amplitude) and reach distance. Measures of the initial position of the COP and the excursion of the COP revealed no age-related differences in balance control. Furthermore, balance control, measured by the amplitude of COP movement over the course of the reaching tasks, indicated no differences between the age groups for the least difficult and most difficult tasks. For tasks of moderate difficulty, however, older children displayed levels of balance control similar to younger children for some tasks and higher levels of balance control, similar to adults, for others. This study suggests that (1) process-based measures of balance control are more sensitive in detecting age-related differences, and (2) balance control depends upon both age and the difficulty of the task being performed.     

Effects of task difficulty on use of advice

Although prior studies have found that people generally underweight advice from others, such discounting of advice is not universal. Two studies examined the impact of task difficulty on the use of advice. In both studies, the strategy participants used to weigh advice varied with task difficulty even when it should not have. In particular, the results show that people tend to overweight advice on difficult tasks and underweight advice on easy tasks. This pattern held regardless of whether advice was automatically provided or whether people had to seek it out. The paper discusses implications for the circumstances under which people will be open to influence by advisors. Copyright © 2006 John Wiley & Sons, Ltd.     

Self-esteem and affect as information

This research tests whether people with high self-esteem are more informed by their emotions than are people with low self-esteem. In Study 1, participants listened to a series of disturbing baby cries, rated how much distress these cries conveyed, and reported their own emotional reactions to the cries. As predicted, the relation between participants' emotional reactions and their cry ratings was strongest at higher levels of self-esteem. In Study 2, self-esteem again determined how strongly participants' own emotional reactions influenced their baby cry ratings, even though esteem was measured weeks before the experiment and even after controlling for social desirability. Study 3 manipulated self-regard and showed that the correlation between participants' emotional reactions and their cry ratings was strong for high-regard participants, moderate for control participants, and weak for low-regard participants. These results suggest that self-esteem serves to validate the informational value of feelings.     

Self-esteem,locus of control,and task difficulty as determinants of task performance

One hundred twenty-six high school students responded to questionnaire measures of chronic self-esteem (CSE), task-specific self-esteem (TSSE), and locus of control of reinforcements (L of C) and were given a list of anagrams to solve that varied in level of task difficulty (TD). L of C and (to a lesser extent) TSSE were each related to task performance (TP), multiple R = .51 (p < .01). CSE was not related to TP. The overall relationships of TSSE and L of C with TP were each moderated significantly by TD. The results are discussed in terms of a gradual specification of the “boundary conditions” within which cognitive consistency theory and social learning theory may be applicable.     

Incidental learning as a function of anticipated task difficulty

Three experiments were conducted to demonstrate the effects of motivational arousal, due to anticipated task difficulty, on retention of familiar and unfamiliar incidental materials. Brehm, Wright, Solomon, Silka, and Greenberg (1983) have provided evidence that motivational arousal in immediate anticipation of a task is a nonmonotonic function of task difficulty, with difficult tasks producing a relatively higher level of motivational arousal than easy or impossible tasks. It was predicted that increased motivational arousal would facilitate retention of incidentally presented familiar materials (presumably more easily retained) and interfere with retention of incidentally presented unfamiliar materials (presumably less easily retained). In Study 1, subjects anticipating either an easy or a difficult task were exposed to familiar and unfamiliar first names. The predicted interaction between task difficulty and familiarity on recall of the first names was reliably supported. In Study 2, an impossible task condition was added. The results indicated that an effective impossible condition had not been created. In a third study designed as a procedural modification of Study 2, the predicted nonmonotonic interaction was found. Theoretical implications are discussed.These experiments were ably conducted by Ralph Young, whose help is gratefuly acknowledged. We would like to express our gratitude to Jack Brehm for invaluable suggestions concerning this research.     

On the difficulty of task switching: Assessing the role of task-set inhibition

This study assessed whether or not the difficulty of task switching stems from previous inhibition of the task set. A predictable sequence of univalent stimuli (affording performance of one active task) and bivalent stimuli (affording performance of two tasks) was used in two experiments. Experiment 1 used an alternating-runs paradigm (AABB) and Experiment 2 used a strictly alternating sequence (ABAB). The critical variable was whether the incentive for task-set inhibition was strong (on bivalent trials) or weak (on univalent trials). The question was whether it would be more difficult to switch to a task that previously needed to be inhibited than to a task that did not need to be inhibited. This pattern was not observed in either experiment. Thus, the data provide no evidence that task switching is difficult because of the need to overcome recent task-set inhibition.     

Priming infants to use pattern information in an object individuation task: the role of comparison

There is evidence that 4.5-month-olds do not always use surface pattern to individuate objects but that they can be primed to attend to pattern differences through select experiences. For example, if infants are first shown events in which the pattern of an object predicts its function (dotted containers pound and striped containers pour), they will attend to pattern differences in a subsequent individuation task. However, 4.5-month-olds must see multiple exemplars of the pound and pour events and view the dotted and striped containers together during the events. These results suggest that it is the formation of event categories, in which pattern is linked to object function, that supports pattern priming and that direct comparison of the exemplars facilitates the extraction of event categories. The present research investigated conditions that support the comparison process in 4.5-month-olds. The results revealed that the comparison process was initiated only when the dotted and striped containers were seen directly adjacent to each other; if the containers sat far apart, so that infants had to shift their gaze to compare them, event categories were not extracted. In addition, it was comparison of the two patterned containers, and not comparison of the two function events, that was critical to the formation of event categories. These results join a growing body of research indicating the importance of comparison to category formation in infants and reveal the impact of categorization and comparison processes on object individuation in infancy.     

Social context and perceived task difficulty as mediators of depressive self-evaluation

This study examined two separate, but potentially interactive, influences on depressive self-evaluation: social context and perceptions of task difficulty. First, it was hypothesized that, if negative self-evaluations of depressed individuals are motivated by a desire to elicit attention and sympathy from others, depressed subjects should evaluate themselves more negatively than nondepressed subjects in a public setting, but not when they make self-evaluative judgments in private. Second, it was hypothesized that negative self-evaluation results from a bias to perceive tasks as being intrinsically easy, i.e., if a task is easy, a given score would be evaluated more poorly than if the task were difficult. It was found that the self-evaluations of depressed subjects were influenced by the social context, but not always in a negative direction. Depressed subjects did not differ from nondepressed subjects when performance evaluations were made in private. In a public condition, depressed subjects evaluated themselves more negatively than nondepressed subjects following an easy task, but evaluated themselves more positively following a difficult task. Depressed subjects did not evidence a bias to perceive tasks as being intrinsically easy. Depressed subjects did rate the tasks to be more difficult for themselves than they thought they would be for others and this expectancy was predictive of negative self-evaluation. These results were discussed in terms of alternative self-presentation motives and theories of social cognition. Self-evaluation often involves social comparison and researchers need to attend to the potentially complex interactions among social and cognitive processes.I would like to thank Deborah Davis and Paul Westerholm for their help in data collection, Ruth Maki for her statistical expertise, and the anonymous reviewers for their thoughtful comments. Portions of this paper were presented at the Annual Convention of the American Psychological Association, New Orleans, 1989.     

Object superiority as a function of object coherence and task difficulty

This study addressed the view that object superiority depends on the informativeness or task relevance of particular contexts. It was hypothesized that target search is facilitated to the extent that global properties of a complex stimulus provide informative cues to target location. Results of Experiments 1 and 2 showed that when the target appeared at variable relative positions it was identified better in a coherent context than in an incoherent one. Because the coherent context was presumed to contain informative global cues to location, the results confirmed the hypothesis. Experiment 2 also indicated that when only informative local properties were available, search was facilitated, albeit to a lesser extent than when global properties were available. Overall, the results extend the informativeness view of object superiority effects.     

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.     

Task performance and electromyopotential as functions of task difficulty and EMG feedback

The dearth of empirical research in the application of biofeedback is discussed. Exp. 1 assessed relationships among biofeedback EMG training, EMG levels, cognitive task performance, and task difficulty. 72 subjects (male or female college students) were administered 1 trial on an iconic memory task with either EMG audio feedback, sham EMG audio feedback, or no feedback. Three levels of task difficulty were used. One 20-min. training session significantly lowered EMG responses, and task performance was inversely related to task difficulty. No relationship between EMG level and task performance was observed. Exp. 2 investigated the effect of increased EMG responses on cognitive task performance for one level of difficulty. One biofeedback training session did not significantly increase frontalis EMG, and there was no relationship between increased EMG and task performance.