Temporal characteristics in apparent movement: Omega movement vs. PHI movement

A vertical line stimulus was presented alternately at two positions on an oscillo scope face, with no interstimulus interval. Observation of this stimulus produced haphazard alternation between a number of movement percepts, which were divided into four categories: phi, omega and partial movement, and no movement. Attention to one category did not increase the proportion of time movement in that category it was reported. Proportion of time reported for each category varied differentially as a function of alternation frequency. Upper and lower displacement amplitude limits were measured as a function of frequency for phi and omega movement. Both limits for omega movement differed from those for phi movement. The results imply that phi and omega movement involve separate processing stages in the visual system.     

Perception of movement patterns: tracking of movement

The tracking of complex two-dimensional movement patterns was studied. Subjects were blindfolded, and their right hand moved around stencil patterns in the midsagittal plane, while the left hand concurrently reproduced the right-hand movement. The accuracy with which the left hand shadowed the criterion movements of the right hand was measured in shape and size. Right-hand movements were active or passive. Present tracking performance was contrasted with errors in recall reported by Bairstow and Laszlo (1978). Results showed that tracking performance was accurate. Active and passive criterion movements were tracked differently. Tracking was clearly superior to recall performance.     

Visual feedback,movement learning and the representation of movement

Two experiments on movement learning are reported where the orientation of a visual curve on a graphics terminal, defining a relatively complex arm movement, was either orthogonal to or compatible with the direction of the required movement. In addition, individual differences in spatial orientation and visualization abilities were correlated with motor performance. Results in both experiments showed that equivalent amounts of learning occurred in the two visual conditions. However, during transfer trials to the opposite condition, virtually no transfer occurred for the compatible group when they performed in the orthogonal condition whereas there was tranfer when the orthogonal group performed in the compatible condition. The results supported the idea that very early in learning the orthogonal orientation of visual curve promoted the development of an orientation processing stage which facilitated transrer performance of the orthogonal group. Integrating these results with the past literature on movement learning led to the notion that the orientation information processing stage can be considered a cognitive system that interacts with the image of the act. Finally, contrary to expectations, spatial orientation ability failed to account for any performance while spatial visualization ability moderately correlated with performance.     

Embodied movement consciousness

Phenomenology and the Cognitive Sciences - In two recent papers, I introduced the idea of embodied Rilkean movement knowledge and perception into the current philosophical debate on sports...     

Mind and movement

Voluntary movements embrace both intentional, conscious and post-intentional, largely automatic processes. Here, we examine these types of processes and the relations between them during preparation and execution of voluntary movements. First, a general overview is given about how intentional and post-intentional components are interleaved to enable successful control of purposeful movements. Second, we briefly describe some post-intentional processes that are triggered by preceding intentions. Third, we discuss findings according to which such post-intentional processes or their results can become accessible to conscious awareness. Under such conditions, automatic and conscious processes can co-occur. We show that intentional interventions into post-intentional processes can be overridden by automatic processes, can interfere with automatic processes and can be independent so that their outcomes add to those of automatic processes.     

Visual movement discrimination

Data are presented which support a mathematical model for visual movement perception. An observer’s ability to judge the relative position of two successively presented points of light in an otherwise dark room is shown to diminish as the inter-stimulus interval is increased. However, a measure of visual position memory appears to remain invariant a5 this interval is varied. Neither the degree of head stabilization nor whether viewing is monocular or binocular appreciably alters this measure.     

Grasping movement plans

Despite the great amount of research that has been done regarding the time it takes to move the hand to targets of varying distances and widths, it is unclear whether target distance and width are both represented in movement plans prior to movement initiation. We addressed this question by studying performance in an object manipulation task. Our participants reached out and took hold of a familiar object (a bathroom plunger) to move it to wide or narrow targets of varying heights. Grasp heights on the plunger were additively affected by target height and target width, suggesting that both factors were taken into account by participants prior to moving the plunger from its initial position. Another factor we manipulated was the width of the base from which the plunger was lifted on its way to its next position. This factor also affected grasp heights, but no more so than target widths. The latter result contradicts the view that movement starts are planned in more detail than movement ends, as might be expected from the fact that movement starts come sooner. Together, our results suggest that forthcoming movements are planned in considerable detail. A surprising methodological implication of this study is that recording how people prepare to move can reveal as much—or in some cases more—about what they have planned than can recording their subsequent movements.     

Apparent haptic movement

When Os were presented with ISO-Hz vibrotactile bursts at two loci on the skin of the thigh and permitted to adjust the time between burst onsets, they reported good apparent movement between the loci. The time between stimulus onsets for optimal movement was found to vary directly with the duration of the stimulus. Replication of the experiment with electrocutaneous stimuli at 1 KHz yielded similar results. Comparison of the data with results from a study of visual apparent movement revealed no difference between the two modalities for the relationship between stimulus onset intervals and stimulus duration. The significance of the results for hypotheses about the processes underlying perception of apparent movement is discussed.     

Apparent haptic movement

When as were presented with 150-Hz vibrotactile bursts at two loci on the skin of the thigh and permitted to adjust the time between burst onsets, they reported good apparent movement between the loci. The time between stimulus onsets for optimal movement was found to vary directly with the duration of the stimulus. Replication of the experiment with electrocutaneous stimuli at 1 KHz yielded similar results. Comparison of the data with results from a study of visual apparent movement revealed no difference between the two modalities for the relationship between stimulus onset intervals and stimulus duration. The significance of the results for hypotheses about the processes underlying perception of apparent movement is discussed.     

Children's autokinetic movement as a function of inferred movement of target shape

Four target shapes, a control stimulus (circle) and one each representing geometrical (arrow), representational (car), and symbolic (cross) implied movement were presented to 10 children in each of five age groups of boys and girls (4, 6, 8, 10, 12 yr.) in an autokinetic movement task. While there were no differences in direction of perceived movement with regard to the control stimulus (circle), all other target shapes showed a decrease in the effects of implied movement with increases in age. The minor sex differences were not reported.     

Visual movement perception: A comparison of absolute and relative movement discrimination

It is proposed that there are two types of visual movement perception, absolute and relative. The former occurs when an object is seen to move in an otherwise homogeneous (or at least locally homogeneous) visual field. Relative judgments occur when one object is seen to move with respect to another, i.e., the separation between them is seen to change. Quantitative models for both processes are developed, and an experiment reported for which the models seem appropriate. The results appear relevant to a theory of size of length perception as well as to the general perceptual issue of absolute and relative judgments.     

The presumption of movement

The conceptualisation of movement has always been problematical for Western thought, ever since Parmenides declared our incapacity to conceptualise the plurality of change because our self-identical thought can only know an identical being. Exploiting this peculiar feature and constraint on our thought, Zeno of Elea devised his famous paradoxes of movement in which he shows that the passage from a position to movement cannot be conceptualised. In this paper, I argue that this same constraint is at the root of our incapacity to conceptualise the unseen movement at the micro-level and that the aporetic idea of super-position far from opening the gate on a deeper reality is a symptomatic word for this lack of understanding.

Bilateral apparent haptic movement

When Os are permitted to manipulate the interstimulus onset interval (ISOI) to obtain optimal apparent movement between two ipsilateral vibrotactile stimuli, a consistent quantitative relation between ISOI and stimulus duration appears. The present report describes conditions for movement between contralaterally-placed stimuli, and shows that whereas movement is qualitatively incomplete, the aforementioned relation is still evident. The results are discussed in the light of recent work in both visual apparent movement and complex patterns of stimulation on the skin.     

Perceptions of coordinated movement

BackgroundHumans are highly social creatures who use others' movements to evaluate their social competencies. Smooth movement specifically signals an attractive, trustworthy or competent person. Those with Developmental Coordination Disorder (DCD), have peer relationship difficulties and lower sociometric preference scores. However, the relationship of perception of poor movement coordination to stereotyping has not been directly demonstrated.AimWe aimed to describe typically developing individuals' social stereotyping of individuals with and without DCD from minimal visual cues.Method3D motion capture tracked the movement of four ‘targets’ (two adult males with DCD and two male controls) in a variety of everyday scenarios. Kinematic footage of the target's movements was presented as a point-light-display to 319 typically developing adults who used The Rating Scale of Social Competence to report perceptions of the target's social competencies.ResultsTargets with DCD were rated as having significantly lower social competence (M = 3.37, SD = 0.93) than controls (M = 3.46, SD = 0.89) t(269) = −5.656; p < 0.001, Cohen's d = 0.34.DiscussionHumans incorporate minimal information on movement fluency to evaluate others' social competencies, including individuals with DCD. Such stereotyping may be automatic and may be an ill-understood mechanism sustaining persistent rejection by peers for individuals with DCD and higher rates of loneliness, isolation and mental disorders. In addition, our study expands research on competence-based stereotyping to a new applied domain, confirming the minimal cues needed to initiate stereotyping of the competencies of others.