Spatial Conceptual Influences on the Coordination of Bimanual Actions: When a Dual Task Becomes a Single Task

When the left and right hands produce 2 different rhythms simultaneously, coordination of the hands is difficult unless the rhythms can be integrated into a unified temporal pattern. In the present study, the authors investigated whether a similar account can be applied to the spatial domain. Participants (N = 8) produced a movement trajectory of semicircular form in single-limb and bimanual conditions. In the bimanual tasks, 1 limb moved above the other in the frontal plane. Bimanual unified tasks were constructed so that the spatial paths to be produced by the 2 limbs could be easily conceptualized as parts of a unified circle pattern. Bimanual distinct tasks availed a less obvious spatial pattern that would unify the 2 tasks. Performance of the spatial patterns was more accurate in the unified task, despite similar demands placed on the coordination dynamics between the limbs in the 2 cases (e.g., the phase relations). The authors conclude that a dual task becomes a single task, and interlimb interference is reduced, when the spatial patterns produced by the 2 hands form a geometric arrangement that can be conceptualized as a unified representation.     

Multisensory Information in the Control of Complex Motor Actions

ABSTRACT— For many of the complex motor actions we perform, perceptual information is available from several different senses including vision, touch, hearing, and the vestibular system. Here I discuss the use of multisensory information for the control of motor action in three particular domains: aviation, sports, and driving. It is shown that performers in these domains use information from multiple senses—frequently with beneficial effects on performance but sometimes with dangerous consequences. Applied psychologists have taken advantage of our natural tendency to integrate sensory information by designing multimodal displays that compensate for situations in which information from one or more of our senses is unreliable or is unattended due to distraction.     

Age Changes in Interlimb Coupling and the Development of Bimanual Coordination

Changes in interlimb coupling, and their role in the development of bimanual coordination, were studied longitudinally in 6- to 12-month-old infants (N = 6). Infants were observed while they were reaching for simple objects of 2 different sizes. Their use of a uni-versus bimanual strategy for reaching as well as the coupling of their bimanual movements were compared; progress in bimanual coordination of complementary movements was evaluated on 8 different bimanual tasks. The bimanual tasks involved an asymmetrical cooperation between the 2 hands. Although spatiotemporal coupling of bimanual reaching movements did not decrease during the age period studied, infants around 7 months of age used their 2 hands infrequently for reaching. Occurrences of bimanual reaching were particularly low at the session preceding the first bimanual success at a bimanual task. This suggests that the temporal coincidence between greater independence of the 2 hands and progress in bimanual coordination of complementary movements acts in 2 directions: Infants may be more at ease when using their 2 hands in differentiated patterns as the hands move less in synchrony, but, in turn, they may be less likely to move their hands in synchrony as the anticipate mirror manipulations of the object less. The frequency of bimanual reaches increased toward the end of the 1st year. This might have been caused by an increase in the repertoire of bimanual asymmetrical object manipulations and by the fact that the development of bimanual coordination allows infants to manipulate objects with complementary movements even after a bimanual approach toward the object.     

Moving to Directly Cued Locations Abolishes Spatial Interference During Bimanual Actions

Interference is frequently observed during bimanual movements if the two hands perform nonsymmetric actions. We examined the source of bimanual interference in two experiments in which we compared conditions involving symmetric movements with conditions in which the movements were of different amplitudes or different directions. The target movements were cued either symbolically by letters or directly by the onset of the target locations. With symbolic cues, reaction times were longer when the movements of the two hands were not symmetric. With direct cues, reaction times were the same for symmetric and nonsymmetric movements. These results indicate that directly cued actions can be programmed in parallel for the two hands. Our results challenge the hypothesis that the cost to initiate nonsymmetric movements is due to spatial interference in a motor-programming stage. Rather, the cost appears to be caused by stimulus identification, response-selection processes connected to the processing of symbolic cues, or both.     

Spatial perspective taking: Coordination of left-right and near-far spatial dimensions

Second- and fourth-grade children viewed a cylindrical object in nine positions on a square display board marked with a 3 × 3 grid. As the object was placed in each position, children identified the view from 90, 180, or 270° positions around the display from a set of photographs. Perspectives in which the object differed from the child's view in both left-right and near-far dimensions were more difficult than perspectives that only transformed one dimension. Error rates decreased with age. There were no main effects of left-right vs near-far or of observer position. Rates of egocentric responding were high at both ages. We note that the complementary spatial dimension to left-right is near-far not front-back. Moreover, the relative ease of front-back transformations in previous research resulted from distinctive front-back cues on the display objects which enabled subjects to use nonspatial strategies to identify observer perspectives.     

Eyewitness Errors in the Free Recall of Actions

Although eyewitness testimony is often unreliable, its quality is not uniformly poor. Previous research indicates that the most accurate type of testimony involves the unstructured recall of actions. The present study replicates the finding that confabulation, particularly the complete fabrication of nonexistent actions, is rare. Our results also extend earlier work by revealing that the few errors that did occur were spread evenly across subjects—with most subjects making 0 or 1 error and with no subjects making more than 3 errors. Furthermore, action memory errors form a heterogeneous set—there were few commonly recurring or predictable errors. Our attempts to increase error frequency by the use of suggestive implications and rapid action sequences were unsuccessful. Practical aspects of evaluating action memory testimony are discussed, with special reference to cases involving multiple eyewitnesses.     

Rational Actions and the Integration of Knowledge

Summary  The paper emphasizes the role of knowledge dimensions of an action which could be regarded as rational. Rational action usually results of specific decision – making process including selection, evaluation and acceptance of a preferred alternative. This process should integrate not only various types of knowledge but also the interdisciplinary or interdepartmental knowledge integration. The integration of knowledge may cover various forms, especially integration of knowledge relating to different domains, of different quality, of knowledge connected with different goal-orientations. The paper stresses the role of the hitherto known and recognized alternatives. The integration procedures should also include the integration of various spheres and types of knowledge with accepted and justified systems of values.     

The Individuation of Actions

I argue against a view of the individuation of actions endorsed most notably by Hornsby and Davidson. This is the view that in, for example, Anscombe's case of the pumping man, we have a single action which can be described, variously, as a pumping, a poisoning and so on. I argue that, even in the area of the standard arguments against this view, such as that based on the logic of 'by' and the argument from temporal dimensions, the case against the Davidson-Hornsby view has not been made as strong as it ought to have been. I show how those standard arguments can be strengthened; and I argue that the principal considerations adduced in support of the view do not in fact lend it the support that they have been widely thought to lend it. I conclude that the view should be rejected.     

Deontology of Compound Actions

Studia Logica - This paper, being a companion to the book [2] elaborates the deontology of sequential and compound actions based on relational models and formal constructs borrowed from formal...     

Alternative Actions and the Spirit of Consequentialism

The simple idea behind act-consequentialism isthat we ought to choose the action whoseoutcome is better than that of any alternativeaction. In a recent issue of this journal, ErikCarlson has argued that given a reasonableinterpretation of alternative actions thissimple idea cannot be upheld but that the newtheory he proposes nevertheless preserves theact-consequentialist spirit. My aim in thispaper is to show that Carlson is wrong on bothcounts. His theory, contrary to his ownintentions, is not an act-consequentialisttheory. By building on a theory formulated byHolly Smith, I will show that the simple ideacan be upheld. The new theory I will proposehas all the merits of Carlson's theory withoutsharing its demerits.     

The Justification of Paternalistic Actions in Psychotherapy

This article defines the nature of paternalistic interventions in psychotherapy and discusses reasons why the client's right to consent to treatment is important. We describe a reasoning process developed by Culver and Gert (1982) that can be used to determine when paternalistic actions are and are not ethically justifiable in mental health practice. We demonstrate how this procedure may be applied to psychotherapy by using a number of case illustrations.     

Coordination dynamics of the horse-rider system

The authors studied the interaction between rider and horse by measuring their ensemble motions in a trot sequence, comparing 1 expert and 1 novice rider. Whereas the novice's movements displayed transient departures from phase synchrony, the expert's motions were continuously phase-matched with those of the horse. The tight ensemble synchrony between the expert and the horse was accompanied by an increase in the temporal regularity of the oscillations of the trunk of the horse. Observed differences between expert and novice riders indicated that phase synchronization is by no means perfect but requires extended practice. Points of contact between horse and rider may haptically convey effective communication between them.     

Conditioning and the Coordination of Movements

(Krech, D., and Crutchfield, R. S. Theory and Problems of Social Psychology. New York: McGraw-Hill, 1948. Pp. 639.) Reviewed by Gwynne Nettler     

Coordination Dynamics of the Horse-Rider System

The authors studied the interaction between rider and horse by measuring their ensemble motions in a trot sequence, comparing 1 expert and 1 novice rider. Whereas the novice's movements displayed transient departures from phase synchrony, the expert's motions were continuously phase-matched with those of the horse. The tight ensemble synchrony between the expert and the horse was accompanied by an increase in the temporal regularity of the oscillations of the trunk of the horse. Observed differences between expert and novice riders indicated that phase synchronization is by no means perfect but requires extended practice. Points of contact between horse and rider may haptically convey effective communication between them.     

Actions and affordances in syntactic ambiguity resolution

In 2 experiments, eye movements were monitored as participants followed instructions containing temporary syntactic ambiguities (e.g., "Pour the egg in the bowl over the flour"). The authors varied the affordances of task-relevant objects with respect to the action required by the instruction (e.g., whether 1 or both eggs in the visual workspace were in liquid form, allowing them to be poured). The number of candidate objects that could afford the action was found to determine whether listeners initially misinterpreted the ambiguous phrase ("in the bowl") as specifying a location. The findings indicate that syntactic decisions are guided by the listener's situation-specific evaluation of how to achieve the behavioral goal of an utterance.     

具身化空间四卡问题解决的内容效应

利用三个实验探讨了左右、前后(实验1,2)具身化空间四卡问题解决的内容效应,同时探讨了条件推理后件类型(二分变量与连续性变量)对具身化内容效应的影响(实验3)。结果发现:(1)三个实验均表现出在自我参照空间四卡问题解决中,肯定前件和否定后件同时被选择的比率(P-Q)显著高于在经典四卡问题或环境参照空间四卡问题中P-Q卡被选择的比率,从而表现出四卡问题解决存在具身化内容效应;(2)具身化内容效应仅限于后件类型是二分变量的四卡问题;(3)在三个实验中被试均表现出"证真偏向"。具身化空间四卡问题解决的内容效应支持了条件推理领域特异性理论。