EDRS PRICE DESCRIPTORS Thorsheim , Howard I . ; And Others Visual and Kinesthetic Components of Pursuit - Tracking

Seventy-five Ss trained on a pursuit rotor for 10 trials, with ambient illumination from a strobe light flashing at frequencies of either 2, 5, 10, 15, or 20/sec. A transfer trial followed, with a strobe flashing frequency of 10/sec for all Ss. Results supported hypotheses derived from Adams' (1971) closed-loop theory of motor learning that (a) performance would improve during training as a function of amount of visual feedback available, and that (b) if after training visual feedback was reduced, performance would bemaintained to the extent that kinesthetic feedback had been learned to be relied upon as an alternate, compensatory, feedback loop. U S OE PAR TMENT OF HEALTH. EDUCATION & WELFARE NATIONAL INSTITUTE OF EDUCATION ', 00C BEEN NFPI0 n.Cf'D Ev.A;,v As WI WOY F I.' 0% %r 0, I ON OWN.ONS icsau, cut , .4(0 Tt If 0, t 1,0s ON POt ,CY Visual and Kinesthetic Components of Pursuit-Tracking Performancel Howard I. Thorsheim, Lanning Houston, and Christopher Badger2 Saint Olaf College, Northfield, Minnesota 55057 Adams' (1971) closed-loop theory of motor learning postulates a perceptual trace which S develops as he receives error information in the form of sensory feedback from task performance. The theory predicts that the perceptaal trace is what S uses as the reference against which to compare and modify subsequent movements on the basis of knowledge-of-results (KR) received. The theory also predicts that after a relatively large amount of training, performance can continue when KR is withdrawn, because S has built a perceptual trace as an internalized reference. It is consistent with the theory to assume that boTh visual and kinesthetic sensory feedback should contribute error information, to the building of the perceptual trace. The hypotheses of the study are two: (a) Performance will improve during training .as a function of the amount of visual feedback available, and (b) That if after a relatively large amount of training the opportunity for visual feedback is reduced, performance will be maintainined to the extent that a perceptual trace has been built with kinesthetic feedback as an alternate feedback loop. Method Procedure. On each of 12 one-min trials, S used a hinged stylus to track a target on a pursuit apparatus. Intertrial intervals of 20 sec were used to control for massed practice effects. The 12 trials included (a) pretest [trial 1), (h) training [trials 2-11], and Thorsheim, Houston, an 'adger 2 (c) transfer [trial 12]. The independent variable was the flash frequency of a strobe light during training, which provided the only source of target illumination. The pretest was the E:tme for everyone, with a strobe flash frequency of 40/sec. Training trials had one of five different flash frequencies (2, 5, 10, 15, or 20/sec). The transfer trial was the same for everyone, with a strobe flash frequency of 10/sec. The flash frequencies for pretest, training, and transfer were selected on the basis of findings from a pilot study conducted. For all 12 trials, a 15 W red bulb was lighted as a source of KR whenever S's stylus contacted the target. The red light was positioned below and adjacent to the pursuit apparatus, and did not illuminate the target either directly or indirectly. Thus the present study was similar to past studies in which KR has been provided during the training stages of a tracking task (e.g., Williams & Briggs, 1962). It was different from past studies in that the KR was continued for the transfer trial, and was not removed. Instead on the transfer trial, the present study made the visual feedback loop more or less effective (relative to training) as a source of error information. Subjects. Seventy-five paid undergraduate volunteers, both male and female, were divided randomly into five groups, with the constraints that there be 15 Ss per group, and approximately the same number of male and female Ss. Each group was assigned one of the five flash frequencies for training. Apparatus. A General Radio 648-A Strobolux strobe-light was Thorshelm, Houston, and Badger 3 driven by a General. Radio 631-D1. Strobotac tachometer to produce the required flash frequencies. The duration of any single flash was 50 psec. Durations of trials and intertrial intervals were regulated by two cycling Hunter timers. A Hunter Klockounter was used to record the dependent variable (time-on-target) in sec for each trial. The strobe-light was positioned .3 m from the center of the pursuit apparatus. S stood behind the strobe-light and held his preferred arm over the top of the strobe-light box to perform the tracking task. To reduce reflected light, the wallL; and ceiling of the 1.35 by 2.2 m cubicle were covered with soft black flannel cloth, and the floor was covered with nonreflecting black rubber-coated fabric. The target of the pursuit apparatus was an aluminum disk 2.5 cm in diameter, and was positioned 12 cm from the center of the 17 cm in diameter Prestwood platform of the pursuit apparatus. Throughout the experiment, the target was checked regularly for abrasion or pitting, and periodically polished. The platform of the apparatus rotated clockwise at 33 rpm, and its surface was 93 cm above the floor S