An Examination of Rapid Positioning Movements with Spatiotemporal Constraints

Unidirectional positioning movements with spatiotemporal-constraints were examined as a test of impulse-timing theory (Schmidt, 1976; 1980; Wallace, 1981). Movements were examined at the kinematic, kinetic, and neuromuscular levels in three experiments. In the first experiment, displacement was held constant while five different movement times were examined. Both amplitudes and durations of the EMG and the kinetic variables were related to movement time. The results generally support the impulse-timing model. In the second experiment, movements were performed to a target at each of four distances in a constant movement time. EMG and force amplitudes and, unexpectedly, accelerative-force duration were modulated to achieve changes in displacement when movement time was constant. In the third experiment, movement time and displacement were simultaneously varied resulting in four conditions with equal average velocities. The results of this experiment were not as clear and exhibited individual differences. EMG duration did not always vary with changes in movement time. The results of all three experiments could not be adequately accounted for by the impulse-timing model.     

Generation of Bimanual Trajectories of Disparate Eccentricity: Levels of Interference and Spontaneous Changes Over Practice

The authors examined intermanual interactions of 2 hands that were required to concurrently follow trajectories that differed in eccentricity. Ten healthy participants attempted to learn to trace 2 figures, a circle and an ellipse, with bilaterally isochronous (1:1) timing demands. Initial unimanual trials were followed by bilateral practice comprising 750 movement cycles. Two objectives were addressed: The authors' primary aim was to determine if kinematic interlimb interference is evident independent of spatial and temporal interference and to observe the potential practice-related changes in the nature of that interference. That test was afforded by participants' natural tendency to draw a circle with a relatively constant tangential velocity and an ellipse with a systematically varying velocity. A second aim was to observe the nature of spontaneous changes in the performance of each individual effector, and in the relationship between effectors, across practice. Those objectives were specifically addressed in a context in which augmented feedback was not available to direct the learners' attention to a particular feature of performance. The results suggested that interlimb assimilation of spatial features is the primary source of interference for that task and that apparent effects at the kinematic level are the secondary, indirect product of spatial coupling. Those results were found across blocks of practice. With respect to nondirected performance changes, substantially less improvement was evident in the performance of each individual effector than in the reduction of interlimb interference. Specifically, no practice-related changes in temporal variability or velocity bias, and minimal changes in trajectory smoothness, were evident in individual limbs. Conversely, significant reductions were observed in the variability of relative phase between limbs and in the magnitude of interlimb phase lag.     

The Metamorphosis of Projective Methods

Early approaches to projective methods emphasized the use of unstructured materials as stimuli designed to elicit symbolic material within a psychoanalytic framework. Current theorizing concerning projective methods emphasizes the multi-level nature of test behavior and the unique role that projective methods play in the assessment armamentarium.     

Task Importance Effects on Prospective Memory Strategy Use

Mnemonic strategies generally improve prospective memory (PM) performance. However, little is known about why people use such strategies. In the Motivational‐Cognitive Prospective Memory model, task importance is thought to influence performance via multiple mechanisms, including increased strategy use. Our main purpose was to test this mechanism: higher PM task importance was hypothesized to cause greater strategy use. We also tested whether importance would specifically increase the use of more effective (external) strategies. Participants reported their strategy use for two hypothetical PM tasks. As predicted, they listed more strategies for more important tasks. This result demonstrates one mechanism for motivational effects in early phases of the task. We found weaker support for the prediction that participants would selectively increase their use of better strategies for more important tasks. This finding supports a relatively pessimistic view of meta‐memory in PM, at least when it comes to modulating one's use of dependable strategies. Copyright © 2013 John Wiley & Sons, Ltd.     

Intrusive and avoidant ideation among females pursuing infertility treatment

Abstract

It was shown that infertility and its treatment constitute a stressful experience for women, reflected particularly in disturbing intrusive ideation about the stress source. Infertility patients reported levels of intrusive ideation significantly higher than routine gynecologic patients and not significantly different from levels of psychiatric outpatients being treated for stress reactions to traumatic events. Intrusive ideation also predicted the degree of self-reported infertility-specific distress and dysfunction, further clarifying the key role of such ideation in the experience. Finally, as hypothesized, the frustration level of the treatment experience (as indexed by the number of infertility treatment methods attempted) predicted avoidant ideation. Implications for managing the psychological distress and disruption associated with the infertility treatment experience were discussed.     

What is Locke's Theory of Representation?

On a currently popular reading of Locke, an idea represents its cause, or what God intended to be its cause. Against Martha Bolton and my former self (among others), I argue that Locke cannot hold such a view, since it sins against his epistemology and theory of abstraction. I argue that Locke is committed to a resemblance theory of representation, with the result that ideas of secondary qualities are not representations.     

Is the truth table task mistaken?

There is ample evidence that in classical truth table task experiments false antecedents are judged as “irrelevant”. Instead of interpreting this in support of a suppositional representation of conditionals, Schroyens (2010a Schroyens, W. 2010a. Mistaking the instance for the rule: A critical analysis of the truth-table evaluation paradigm. Quarterly Journal of Experimental Psychology, 63: 246–259. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar], 2010b Schroyens, W. 2010b. A meta-analytic review of thinking about what is true, possible, and irrelevant in reasoning from or reasoning about conditional propositions. European Journal of Cognitive Psychology, 22: 897–921. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) attributes it to the induction problem: the impossibility of establishing the truth of a universal claim on the basis of a single case. In the first experiment a truth table task with four options is administered and the correlation with intelligence is inspected. It is observed that “undetermined” is chosen in one third of the judgements and “irrelevant” in another third. A positive correlation is revealed between intelligence and the number of “irrelevant” and “undetermined” judgements. The data do not exclude that a part of the “irrelevant” judgements in classical truth table task experiments might be caused by the induction problem. In the second experiment participants are presented with a simplified four-option truth table task and asked for a justification of their judgements. These justifications show the induction problem is not the reason for choosing the “irrelevant” or “undetermined” option, which is supportive for a suppositional representation of conditionals.