Effects on prism adaptation of duration and timing of visual feedback during pointing

In two experiments, we investigated the effects of duration of visual feedback of the pointing limb and the time (early to late) in the movement when the limb first becomes visible (timing of visual feedback). Timing, rather than duration of visual feedback, proved to have the greater effect on the relative magnitude of visual and proprioceptive adaptation. Visual adaptation increased smoothly with feedback delay, but corresponding decreases in proprioceptive adaptation underwent an additional sharp change when feedback was delayed until about three-fourths of the way to the terminal limb position. These results are consistent with the idea that visual and proprioceptive adaptation are mediated by exclusive processes. Change in the limb position sense (i.e., proprioceptive adaptation) may be produced by visual guidance of the pointing limb, and view of the limb early in the pointing movement seems to be critical for such visual guidance. The limb may be ballistically released as it nears the terminal position, and, thereafter, any opportunity for visual guidance (i.e., view of the limb) is not effective. On the other hand, change in the eye position sense (i.e., visual adaptation) may be mediated by proprioceptive guidance of the eye; the eyes may track the imaged position of the nonvisible limb. Such proprioceptive guidance seems to be solely a function of the distance moved before the limb becomes visible.     

Target and arm observation effects on adaptation to prism displacement

Adaptation to displacement of objects in the visual field was studied as a function of preexposure test targets being absent or present in that field and lateral arm movement requiring no pointing at targets being observed or unobservable during prism exposure. Significantly greater adaptation was found when targets present during prism exposure were the same as those present during pre and postexposure test conditions. In addition, greater adaptation was found when S was permitted observation of lateral arm movement during prism exposure. Greatest adaptation was produced when both targets were present and arm movement was observable during prism exposure. In addition, when three targets were present during prism exposure, the greatest amount of adaptation was found for targets on S’s prismatically shifted visual field periphery.     

Generalization of prism adaptation

Prism exposure produces 2 kinds of adaptive response. Recalibration is ordinary strategic remapping of spatially coded movement commands to rapidly reduce performance error. Realignment is the extraordinary process of transforming spatial maps to bring the origins of coordinate systems into correspondence. Realignment occurs when spatial discordance signals noncorrespondence between spatial maps. In Experiment 1, generalization of recalibration aftereffects from prism exposure to postexposure depended upon the similarity of target pointing limb postures. Realignment aftereffects generalized to the spatial maps involved in exposure. In Experiment 2, the 2 kinds of aftereffects were measured for 3 test positions, one of which was the exposure training position. Recalibration aftereffects generalized nonlinearly, while realignment aftereffects generalized linearly, replicating Bedford (1989, 1993a) using a more familiar prism adaptation paradigm. Recalibration and realignment require methods for distinguishing their relative contribution to prism adaptation.     

Effects of movement duration and visual feedback on visual and proprioceptive components of prism adaptation

While looking through laterally displacing prisms, subjects pointed sagittally 80 times at an objectively straight-ahead target, completing a reciprocal out-and-back pointing movement ever 1, 3, or 6 s. Visual feedback was available early in the pointing movement or only late at the end of the movement. Aftereffect measures of adaptive shift (obtained after every 10 pointing trials) showed adaptive change only in limb position sense (i.e., proprioceptive adaptation) when movement duration was 1 s, regardless of visual feedback condition; but as movement duration increased, adaptive change in the eye position sense (i.e., visual adaptation) increased while proprioceptive adaptation decreased, especially for the late visual feedback condition. Regardless of visual feedback condition, proprioceptive adaptation showed the maximal rate of growth with the 1-s movement duration, whereas visual adaptation showed maximal growth with the 6-s movement duration. These results provide additional support for a model of adaptive spatial mapping in which the direction of strategically flexible coordination (guidance) between eye and limb (and consequently the locus of adaptive spatial mapping) is jointly determined by movement duration and timing of visual feedback. An additional effect of movement duration is to determine the rate of discordant inputs. Maximal growth of adaptation occurs when the input rate matches the response time of the spatial mapping function.     

Understanding the motivational effects of procedural and informational justice in feedback processes

Building upon traditional feedback models, this study examined the role of fair treatment in feedback contexts. Structural equation modelling using data from 236 undergraduate students highlighted perceived accuracy as a mediator in the credibility‐motivation relationship as well as a relationship between accuracy and perceptions of procedural and informational justice. In addition, the results showed that the motivating effects of feedback accuracy partially occurred through procedural justice perceptions. Tests of an alternative model also demonstrated the interactive effects of credibility and accuracy on justice perceptions. Overall, this study provides insight into the role of fairness in appraisal processes, as well as how fairness might enhance recipients' reactions to appraisal and, subsequently, the effectiveness of appraisal systems.     

The role of acceleration information in prism adaptation

Two experiments were performed in which the acceleration component of limb movement information during prism exposure was manipulated, by controlling the trajectory and visibility of arm movement. When limb movements were confined to a lateral motion on a linear track, adaptation was evident when arm movement reversal at the end of the trajectory could be viewed (nonoccluded arm-movement reversal conditions). No adaptation occurred in the occluded arm-movement reversal condition. When movements were made on a curved track, adaptation was evident in both the nonoccluded and the occluded arm-movement reversal conditions. The results indicate that the acceleration component of reafferent stimulation may be critical in prism adaptation when no error information is available.     

Discriminative conditioning of prism adaptation

Two experiments were used to demonstrate that adaptation to ll-deg prism displacement can be conditioned to the stimuli associated with the goggles in which the prisms are housed. In Experiment 1 it was found that repeated alternation between a series of target-pointing responses while wearing prism goggles and a series of responses without prism goggles led to larger adaptive shift when S was tested with nondisplacing goggles than when tested without goggles. The results of Experiment 2 indicated that the adaptation revealed in the first experiment was primarily proprioceptive, rather than visual. Surprisingly, most Ss reported greater difficulty during the exposure period in overcoming the negative aftereffect than they did the prism-induced error.     

Intermanual transfer of prism adaptation

The authors measured intermanual transfer in participants (N = 48) whose exposed or unexposed right or left hand was tested 1st after participants experienced prismatic displacement. Test order did not affect either participants' performance during prismatic exposure or the usual aftereffects, but transfer occurred only when the authors tested the exposed right hand 1st. Transfer did not occur, and proprioceptive shift for the exposed left limb decreased when the authors tested the unexposed right limb 1st. The present results suggest that transfer occurs during testing for aftereffects of prism exposure, but not during prism exposure itself, as researchers have previously assumed. Results are consistent with those of previous research that has shown that limb control is lateralized in opposite hemispheres and that the left hemisphere contains a spatial map only for the right limb.     

The informational and facilitative effects of an audience upon expression and the evaluation of humorous stimuli

A study was conducted to investigate the facilitative and informational effects of an audience upon a subject's expressive behavior (i.e., smiling and laughing) and his rating of cartoon stimuli. Forty-eight male and 48 female subjects were shown single frame cartoons accompanied by audience laughter and were asked to rate the cartoons for funniness and liking. Two aspects of the audience were varied: the appropriateness of the audience setting for the expression of laughter (the audience was identified as viewing the cartoons in a classroom or party condition) and the consistency of the audience's laughter (either consistently high for both good and poor quality cartoons, or varied, high for good cartoons and low for poor cartoons). The findings show that male subjects discriminated most between good and poor cartoons when the audience laughter was in an appropriate (party) setting and was varied with cartoon quality. They discriminated least (gave similar ratings to good and poor cartoons) to a party audience that expressed consistently high laughter. No convergence in rating of good and poor cartoons was found in the inappropriate classroom conditions. These results support the hypothesis that male subjects use the audience laughter as information about cartoon quality either averaging or discounting the audience laughter with the perceived quality of the cartoon. For female subjects, on the other hand, the party audience and consistently high laughter elevated observed expressions of mirth and elevated cartoon ratings. The fact that variables which increased expressive behavior also increased ratings is consistent with the two-part hypothesis that female subjects base their cartoon ratings on their feeling states, and that these feelings states reflect the pooled impact of the quality of the cartoons and the subject's expressive behavior. There was no overall difference in amount of audience influence for male and female subjects. Thus, male and female subjects differ in the way they are influenced by an audience rather than in how much they are influenced.     

Development of the third component in prism adaptation: effects of active and passive movement

Adaptation to prismatically displaced vision was assessed using a factorial design involving active or passive exposure movement, active or passive test movement, and target location. Tests of visual shift, ipsilateral and contralateral proprioceptive shift, and ipsilateral and contralateral target-pointing shift were made at the completion of 6, 12, 24, 48, and 96 exposure trials. During the early stages of adaptation (< 48 exposure trials), changes in ipsilateral target pointing were completely accounted for by the sum of the visual and ipsilateral proprioceptive changes. Following longer exposure durations, evidence of a third component was obtained, but only when exposure and test movements were the same (i.e., active-active and passive-passive conditions). The acquisition of such movement-specific response tendencies was interpreted as indicating that the third component represents a change in a central program or schema, which is responsible for guiding a limb to an externally specified location. Target location had no effect on the presence or magnitude of the third component, and there was no indication that the third component transferred intermanually.     

Perceptions of teachers' general and informational feedback and intrinsic motivation in physical education: two-year effects

Relative change or stability of perceived positive general feedback and perceived informational feedback and their influence on students' intrinsic motivation in physical education over two years were examined. 302 students, ages 11 to 15 years, responded to the Perception of Teacher's Feedback questionnaire. Two years later, these students filled out the questionnaire again, along with a modified version of the Sport Motivation Scale. Analysis showed that both types of perceived feedback exhibited moderate stability over the two years. Perceived positive general feedback demonstrated a significant direct effect on students' intrinsic motivation measured concurrently in physical education. Further, fixing to zero the effect of perceived positive general feedback on intrinsic motivation measured concurrently, an effect emerged over the two years.