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Biomedical subjects

M G Fischman

Publications and source records attributed to M G Fischman.

15 recordsLinked to original sources
PubMed2000

Manipulations of sensory information: a test of the hypothesis of redundancy of knowledge of results.

The hypothesis of redundancy in knowledge of results was examined by manipulating the amount and location of sensory information available to participants performing a coincident anticipation timing task. Either the last 8 lights or the last 16 lights of the visual display were visible to 48 participants. Following an acquisition phase, learning was tested over immediate (5-min.) and delayed (24-hr.) retention intervals. The main finding was that performance was better when knowledge of results was present, regardless of the amount of sensory information available; therefore, knowledge of results was not redundant information for learning this task.

Adult↗
PubMed1999

Kinematic characteristics of aiming movements as a function of temporal and spatial constraints.

This study investigated, in aiming movements, the conditions needed to produce a single movement and those needed to produce secondary submovements. Using a 2x2 (Temporal Constraint x Spatial Constraint) factorial design with repeated measures on both factors, subjects moved a stylus from a starting position to a target position 12 cm away. They participated in two testing sessions on consecutive days. The first session involved two nonrestrictive target (a set of crosshairs) conditions, moving to the target either within a goal of 400 ms (temporal-accuracy procedure) or within a minimum time (time-minimization procedure). In the second session the subjects performed two strict-target (circle) conditions, moving to the target either within a goal of 400 ms or within a minimum time. The results showed that the two strict-target conditions had a greater percentage of trials containing multiple-submovements than the two nonrestrictive target conditions, regardless of temporal requirements. Therefore, whether an aiming movement contains a single movement or multiple submovements may be a function of spatial constraints regardless of temporal constraints. It appears that with respect to the nature of the speed-accuracy tradeoff, spatial constraints are an important factor.

Adult↗
PubMed1998

Constraints on grip-selection: minimizing awkwardness.

In picking up and manipulating an object, the selection of an initial grip (overhand versus underhand) often depends on how comfortable the hand and arm will be at the end of the movement. This effect has been called "end-state comfort" and seems to be an important constraint in grip-selection. The present experiment further explored this effect by selecting a task that would ensure a comfortable ending position regardless of the initial choice of grip. 206 undergraduates picked up a cardboard paper-towel roll from a horizontal position and placed one end down on a table. Analysis showed a clear preference for the overhand grip, as 78% of the participants chose this grip. In addition, more women preferred the overhand grip than men. The findings indicate that people may be sensitive to minimizing awkwardness in both terminal and initial positions.

Biomechanical Phenomena↗
PubMed1996

Effects of bandwidth feedback on delayed retention of a movement timing task.

The effectiveness of broad and narrow bandwidth feedback for learning a 2-segment timing task was tested over short-term (10-min.) and longer-term (2-day) retention intervals. The main finding was that bandwidth feedback groups deteriorated in accuracy across the retention tests, raising questions about the effectiveness of bandwidth feedback for longer-term learning.

Adult↗
PubMed1994

Motor skill acquisition and retention as a function of average feedback, summary feedback, and performance variability.

Summary feedback involves withholding feedback from subjects until the last trial in a block is completed, and then presenting feedback about each trial. A variation of this method, called average feedback (Young & Schmidt, 1992), presents subjects with only the mean of the trial block. We investigated whether these methods have similar effects on acquisition and retention of a simple motor skill. Five groups of subjects (n = 16 per group) performed 60 acquisition trials of an aiming task involving both spatial and temporal accuracy. We presented average and summary feedback based on either 5-trial blocks or 15-trial blocks and compared these schedules with every-trial feedback. During acquisition, all groups improved with practice, with a slight tendency for the every-trial condition to have less absolute error than the longer summary and average conditions. Analysis of delayed no-feedback retention tests, however, revealed a strong advantage for the 5-trial summary and average conditions compared with the every-trial condition. In addition, we found that for long blocks of acquisition trials without augmented feedback, the performance variability of those trials was associated with retention performance. Results are discussed in terms of how these different manipulations may make feedback less useful during acquisition, but foster the use of certain information processing activities that enhance overall learning.

Journal Article↗
PubMed1994

Evidence limiting the subtended-angle hypothesis of response-programming delays.

In 1991 Sidaway proposed an alternative explanation to account for the traditional effect of response complexity on programming time. He suggested that rather than number of movement parts per se, it is the directional accuracy demand of a response, as quantified by the "subtended angle," that constrains the movement initiation and produces programming delays. In Sidaway's experiments targets were positioned so that the first target was always closest to the starting position, with subsequent targets positioned further away from the start. This study tested the subtended-angle hypothesis by placing the first target furthest from the starting position, with subsequent targets struck by reversing direction and coming back toward the start. 30 subjects performed two aiming responses, a discrete 1-TAP condition and a serial 3-REVERSE condition. Because the subtended angle was identical in both conditions, there should be no difference in programming time. Our analyses, however, showed a significant effect for number of targets. Mean reaction time was longer for 3-REVERSE than for 1-TAP. These results argue against a strict constraint interpretation based on subtended angle and suggest that, under certain conditions, number of movement parts can still affect delays in response programming.

Adult↗
PubMed1992

Children's one-hand catching as a function of age, gender, and ball location.

A sizable body of literature exists on the product characteristics and developmental sequence for two-hand catching, but to date there is no description of the developmental characteristics of simple one-hand catching in young children. This study investigated the influence of age, gender, and ball location on children's one-hand catching. Boys and girls (N = 240) ranging in age from 5 to 12 years attempted to catch a total of 24 tennis balls, tossed from a 9-ft distance. Tosses were directed to four locations: (a) Waist, (b) Shoulder, (c) Above-the-Head, and (d) Out-to-the-Side. Descriptive data consisted of the percentage of successful catches at each ball location, and the hand-arm orientation selected by the child as a function of ball location. Results revealed that catching performance improved with age, boys caught more balls than girls, ball location influenced catching success, and, in general, the location of the toss constrained the child's selection of an appropriate hand-arm orientation. With the possible exception of the Shoulder location for girls, even very young children are sensitive to the perceptual aspects of the toss and respond with an appropriate orientation.

Age Factors↗
PubMed1991

Influence of extended practice on programming time, movement time, and transfer in simple target-striking responses.

Two experiments describe the effects of extended practice on the development of motor control programs for simple target-striking responses. In Experiment 1,400 right-hand trials of simple one-target and two-target striking tasks were performed. In Experiment 2,600 practice trials were given. Overall reaction time (RT) was faster for the one-target condition in both experiments, supporting a response complexity effect. Movement time (MT) for both conditions improved linearly with practice, suggesting that development of the motor control programs was still occurring. Subjects then transferred to a three-target condition for 50 trials, performing the transfer task with the right hand in Experiment 1, and with right and left hands in Experiment 2. Transfer to the three-target conditions produced execution errors in the form of failure to contact the second target and repetitive tapping on the third target. These results suggest that extensive practice may serve to firmly entrench a response sequence, making it difficult to implement a similar, but unique, motor control program. An interpretation in terms of automaticity and enhanced priming of behavioral and neural pathways is offered to account for these results.

Journal Article↗
PubMed1990

Reaction time and index of difficulty in target-striking tasks with changes in direction.

Reaction time (RT) for two three-segment target-striking responses involving changes in direction of movement was studied as a function of differences in their additive index . . . index of difficulty (A-ID). In one condition the A-ID was 9.96 and in the other, 6.76. For 16 right-handed university students, mean RT was significantly faster for the condition in which the index was 6.76. Movement times were consistent with Fitts' Law. The data support Sidaway, Christina, and Shea's 1988 prediction that for target-striking movements with changes of direction, RT is a function of the cumulative series of movement constraints.

Adult↗
PubMed1989

Influence of a baseball glove on the nature of errors produced in simple one-hand catching.

The influence of a baseball glove on the positioning and grasping components of one-hand catching was studied under both vision impaired and unimpaired conditions. Skilled softball and baseball players (N = 20) caught tennis balls barehand and softballs with a fielder's glove. In half of the trials, a screen positioned alongside the subject's head blocked vision of the catching hand. All trials were videotaped and errors were categorized by type (position or grasp). Results indicated that with the glove performance was essentially perfect, regardless of the screen condition. Barehand grasping performance, however, was affected by the subject's inability to see his hand to a much greater extent than barehand positioning. We argue that the baseball glove functions to reduce both the positioning accuracy requirements and the grasp timing requirements in simple catching. Peripheral vision of the limb, however, is necessary for controlling the barehand grasp phase.

Adolescent↗
PubMed1986

A note on issues in recent work on one-hand catching.

Whiting's (1986) comments on the necessity of viewing the hand in one-hand catching are acknowledged, and several empirical issues are raised for consideration. These issues revolve around (a) the two components of one-hand catching, (b) lack of independence of position and grasp errors, and (c) specificity of skill.

Journal Article↗
PubMed1985

Skill level, vision, and proprioception in simple one-hand catching.

Two experiments examined the interaction of vision and articular proprioception in simple one-hand catching. In Experiment 1 (N = 18) skilled baseball and softball players used the left and right hands to catch slowly moving tennis balls, while Experiment 2 (N = 16) used novice catchers as subjects. In half the trials, sight of the catching hand was prevented by placing a screen alongside the subjects' face. Results of Experiment 1 revealed that the screen caused minimal disruption of the positioning phase of the catch, with moderate disruption of the grasping phase. However, for the unskilled subjects of Experiment 2, the screen caused considerable disruption of positioning. The data provide only minimal support for Smyth and Marriott' (1982) contention that limb position is inadequately specified by articular proprioception. It is argued that skill level serves as a mediator in the ability to use proprioception for limb positioning, but vision appears necessary to control the precise temporal organization of the grasp phase of one-hand catching.

Journal Article↗
PubMed1984

Programming time as a function of number of movement parts and changes in movement direction.

The question of whether changes seen in simple reaction time (SRT) as a function of response complexity (i.e., number of movement parts) should be considered as differences in the time needed to centrally program a motor response was addressed. Using a large-scale tapping response, 14 subjects contacted from one to five targets positioned in a straight line, while a second group of 14 subjects executed 90 degrees changes in direction in striking the targets. Results revealed that mean SRT and mean premotor time increased linearly as the number of movement parts increased, regardless of whether changes in movement direction had to be programmed, with the greatest increase occurring between one-, and two-part responses. Increases in motor time were not sufficient to account for the sizeable SRT effect. These findings support the position of increased central programming time for more complex responses, and also help establish some of the boundaries of the complexity effect.

Journal Article↗
PubMed1982

Simple reaction time as a function of response complexity: memory drum theory revisited.

The prediction emanating from memory drum theory (Henry & Rogers, 1960') that simple reaction time (SRT) increases as a response becomes more complex (i.e., increases in number of movement parts) was investigated. Experiments 1 (N = 20) and 3 (N = 16) indicated that SRT was longer for responses consisting of two and three parts than it was for a one-part response and this may be interpreted as support for the prediction. Failing to support the prediction, however, was the finding that SRT was essentially the same for responses consisting of two and three parts. This may not be too damaging to the theory because it could simply be reflecting an upper limit in terms of numbers of parts or response duration for causing an increase in SRT. Experiments 2 (N = 20) and 3 revealed an SRT effect between two responses that were supposed to be equal in complexity. At first, this finding appeared to be contrary to the prediction, but it may be interpreted as support for it because one of the responses defined as having one movement part could actually have had two

Journal Article↗