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.     

Kinematic and electromyographic changes that occur as a function of learning a time-constrained aiming task

The present study attempted to examine the changes associated with learning two time-constrained aiming movements at the neuromuscular and behavioral levels of analysis. Electromyographic data and movement kinematics were used to assess changes due to practice. Eight right-handed females were required to perform a 45 degrees horizontal forearm extension in either 200 ms or 500 ms for 100 trials on each of four consecutive days. Both groups demonstrated an improvement in performance and a decrease in within-subject variability in the endpoint response measures, movement trajectory, and myoelectric pattern. With practice, there was a decrease in the amount of cocontraction between the agonist and antagonist muscles during movement execution, which indicated an elimination of unwanted neural activity. For the 200 ms task, the acceleration profile became symmetrical and triphasic myoelectric pattern became evident. The deceleratory phase of the 500 ms task was longer than the acceleratory phase, and a biphasic pattern became apparent. The results suggest that two different control strategies were developed in the execution of the two movements examined. In addition, the relative invariance of the spatial-temporal dependent measures, as compared to the variability of the EMG, led us tot he conclusion that the movement planning hierarchy was concerned with the spatial-temporal domain, whereas the amplitude and timing of muscular activity were planned at a lower level and thus played a subordinate role in movement production.     

Cooperative selection of movements: The optimal selection model

How one selects a movement when faced with alternative ways of doing a task is a central problem in human motor control. Moving the fingertip a short distance can be achieved with any of an infinite number of combinations of knuckle, wrist, elbow, shoulder, and hip movements. The question therefore arises: how is a unique combination chosen? In our model, choice is achieved by consideration of the similarity between the task requirements and the optimal biomechanical performance of each limb segment. Two variants of the model account for the movements that are selected when subjects freely oscillate the fingertip and when they tap against an obstacle. An important feature of both is that the impulse of collision with an obstacle (as in drumming with the hand or tapping with the finger) is assumed to be controlled in part by aiming for a point beyond the surface being struck. Thus, a force-related control variable may be represented and controlled spatially.     

Perspective-Taking Judgments of Medication Acceptance: Inferences from Relative Importance about the Impact and Combination of Information

Perspective-taking judgments of medication acceptance were studied for hypothetical mental health treatment scenarios. Three types of information were manipulated in all possible subsets: level of trust in the medication prescriber, severity of the hypothetical mental health condition being experienced, and the potential side effects of the medication. Subjects made judgments from four perspectives: self perspective and that of three other hypothetical people who were each said to place the most importance on one of the three cues. The results showed individual differences in self-reports of the relative importance of the cues which, in turn, predicted differences in judgment patterns. Subjects modified their cue use when making judgments from the perspectives of hypothetical others. The interaction patterns and rank orders of the perspective-taking judgments resembled the individual differences in judgments made from subjects’ own perspectives, but the perspective-taking judgments showed extreme effects of the most important cue. There was also some influence of subjects’ own perspectives on their perspective-taking judgments. When only a subset of the three cues was given, the judgment pattern depended on the importance of the cue that was omitted. The relative weight averaging model accounted for the judgments of only a minority of the subjects. Models which propose that subjects infer the value of missing information were also unsuccessful in explaining the data of the majority. Modifications of those models are proposed.     

Role conflict and perceptions of gender roles (the case of Israel)

The present study focuses on work—family role conflict among Jewish women employed in a female-typed occupation (secondary school teachers) and a male-typed occupation (university professors). The major hypotheses of the study are that women who work in different occupation types employ different strategies to reduce role conflict and that family roles contribute more to role conflict than work roles. The findings support the hypotheses and show that women in a male-typed occupation spend less time on family and domestic roles, and increase their hours of work. Consequently, their burden at home decreases while their burden at work increases. Because the burden at home contributes more to role conflict than the burden at work, women in male-typed occupations report less role conflict than women in a typically female occupation.An earlier version of this paper was presented at the Society for the Advancement of Socio-Economics Conference, Paris, 1994. We wish to acknowledge our gratitude to Dafna Izraeli for her insightful critique. We also thank the anonymous reviewers for their helpful comments. This research was funded jointly by Schein Institute and The Eshkol Foundation.