Biomedical subjects

A K Travlos

Publications and source records attributed to A K Travlos.

7 recordsLinked to original sources

PubMed1999

Re-examining the temporal locus of knowledge of results (KR): a self-paced approach to learning.

Using a self-paced procedure, the effects of unconfounded temporal locus of KR in the acquisition of a simple linear-positioning task was examined. Changes in the chronological profile of KR delivery were evaluated when participants manipulated the time course of the experiment at their own discretion. 29 participants (18 to 32 years) practiced finding an 8-in. line with no fixed starting and ending points. One-way repeated-measures analyses of variance, simple regression analyses across blocks of practice (30), and Pearson product-moment correlations between the KR-time intervals and the performance scores indicated that (a) under self-paced procedures both the KR-delay and post-KR interval decreased congruently with performance error scores, while the temporal component of the task (movement time) and the ratio between the KR-delay and the post-KR interval remained unchanged, (b) any effect on intertrial interval and interstimulus interval in motor skill acquisition should be examined in terms of the KR-delay and post-KR interval, and (c) the relationship between the performance scores and post-KR interval may be used to indicate the point at which KR is no longer required.

Adolescent↗

PubMed1999

KR-withdrawal and self-paced motor performance.

The purpose of this study was to examine the effects of KR-withdrawal on performance and the chronological profile of KR-delivery following the self-paced procedure and the blank trial technique. 120 participants were randomly separated into 12 groups and practiced finding an 8-in. line with no fixed starting and ending points. Appropriate 12 x 3 (groups by blocks of trials) analyses of variance and a prior contrasts were conducted to analyze all dependent variables (absolute error, variable error, movement time, KR-delay, post-KR interval, and KR-delay by post-KR interval ratio). The results indicated that (a) accuracy decreased significantly when KR was withdrawn early in practice, while the effects of KR-withdrawal later in practice affected accuracy differently. (b) Early in practice, participants performed at the same level of consistency even when KR was withdrawn; however, later in practice, the participants were less variable. (c) Movement time, KR-delay, and post-KR-interval were affected differently during early and later stages of practice. (d) Moderate to high correlations between absolute error and post-KR intervals may indicate the development of mechanisms for error detection.

Adult↗

PubMed1999

More practice does not necessarily enhance transfer of learning: evidence and interpretations.

The purpose of this study was to investigate what was learned and transferred of a criterion task using a transfer task and a self-paced procedure. Based on the results of two previous studies, five durations of practice were specifically selected to examine what can be transferred to a new task after different amounts of practice (40, 75, 100, 125, and 150 acquisition trials) on a criterion task. The criterion task required subjects to practice finding an 8-in. line with no fixed starting and ending points from left to right. The transfer task was different from the criterion task in two dimensions, distance (10-in. line) and direction (right to left). 50 volunteers were randomly assigned into 5 groups. Appropriate 5 x 2 (groups by blocks of practice) analyses of variance and a priori contrasts were conducted for all dependent variables (absolute error, variable error, movement time, KR-delay, post-KR interval, intertrial interval, interstimulus interval, and KR-delay by post-KR interval ratio) to examine the effects of terminal acquisition of the criterion task on the initial performance of the transfer task. Analysis indicated that, during practice, participants developed a functional interaction between performance characteristics and chronological profile of KR-delivery of the criterion task that was transferable to the transfer task. Also, practice beyond a certain point was detrimental to the ability to transfer what was learned.

Adult↗

PubMed1996

Perceived exertion during physical exercise among individuals high and low in fitness.

This study was conducted to investigate the influence of fitness level and gradually increased amounts of exercise on individuals' ratings of perceived exertion (RPE). 20 men served as paid subjects. They were divided into groups of high ( > 56 ml/kg/min.) and low fitness ( < 46 ml/kg/min.) according to their maximal oxygen uptake (VO2 (max)). Participants were required to pedal on a cycle ergometer at a progressively increased workload (every 10 min.) corresponding to 40, 50, 60, 70, and 80% of individual VO2 (max) values. Heart rates, RPE, and core temperatures were recorded every 5th minute after the initiation of exercising at a specific workload. Analysis indicated that, when controlling for VO2 (max) values, elevations of heart rate and core temperature were not affected by fitness. However, highly fit individuals perceived themselves under less exertion than did the group low in fitness. Correlations showed that, taking into consideration fitness, there is a stronger relationship between RPE and heart rate and RPE and core temperature for the highly fit individuals than for the less fit.

Adult↗

PubMed1996

Elevation of core temperature and mental functioning.

The purpose of this study was to investigate whether raised core temperature due to gradually increased amounts of exercise affects concentration and speed of information processing, 20 paid men, separated into groups of high (> 56 ml/kg/min.) and low fitness (< 46 ml/kg/min.) according to their maximal oxygen uptake (VO2max), participated in two experimental conditions (exercise and control). Concentration was measured by the Random Number Generation test of attentional deployment given every 10 min. of cycling at workloads calculated as 40, 50, 60, 70, and 80% of individual VO2max values and 10 min. after exercise cessation (exhaustion). Speed of information processing was estimated by an eight-choice reaction time/movement time task given before and after exercise and 15 min. after exercise cessation. Core temperature was recorded at the same time individuals were administered the psychological tests. Analyses indicated that core temperatures increased significantly as a function of exercise intensity for high and low fitness groups. Correlations among the psychophysiological factors indicated that increases in core temperature were not associated with mental functioning. However, at certain core temperatures, core temperature and average choice reaction time/movement time were associated with participants' fitness.

Adult↗

PubMed1995

Information processing and concentration as a function of fitness level and exercise-induced activation to exhaustion.

To examine the effects of increasing amounts of exercise on attention and speed of information processing 20 paid male subjects were separated into groups of high and low fitness according to their VO2max values. The experiment involved an attentional task (Random Number Generation) that was given after every 10 min. of cycling at work-load resistances calculated as 40%, 50%, 60%, 70%, and 80% of individual VO2max values. An eight-choice reaction time-movement time task was given before and after exercise as well as after a 15-min. recovery period. Individuals were tested within 10 min. after exercise cessation (exhaustion) for concentration and within 15 min. for choice reaction time and movement time to assess whether fitness differentially interacted with these variables. Split-plot factorial analyses of variance suggested that the CNS appeared capable of maintaining performance after 50 min. of exhaustive exercise compared to values obtained at the preexercise condition. A 15-min. recovery period significantly impaired MT but relatively highly fit individuals did not appear to perform the choice RT and concentration tasks better than individuals low in fitness.

Adult↗

PubMed1995

Temporal locus of knowledge of results: a meta-analytic review.

Meta-analysis was performed to evaluate the temporal locus of knowledge of results. An extensive literature review was conducted, yielding 17 published articles suitable for the meta-analyses. These studies were then separated into 2 general categories of acquisition and retention. These categories were subdivided further into KR delay interval, KR delay and motor interpolated activities, KR delay and verbal interpolated activities, post-KR interval, post-KR interval and motor interpolated activities, and post-KR interval and verbal interpolated activities. 6 of the 12 categories gave enough data for the meta-analyses. The categories which showed significant results were KR-delay, post-KR interval, and post-KR interval and verbal interpolated activities in acquisition. Although significant, effect sizes were comparatively small. The discussion of findings focused on effects of the temporal locus of KR and interpolated activities on performance and learning.

Humans↗