More on the reliability of the kinesthetic aftereffects measure and need for stimulation.

Recently, some have argued for a renewed interest in the kinesthetic aftereffects procedure (KAE) as a personality measure even though it may show low test-retest reliability. These arguments indicate that first-session KAE is valid but later-session KAE is not, due to the supposed appearance (in later sessions) of unwanted functional similarity between different aspects of the KAE procedure. Functional similarity leads to reduced reliability and validity of the retest. Data from two new studies do not support this functional similarity hypothesis, but these data do support the KAE by showing test-retest reliability. Also, the data show some new but tentative experimental evidence for the construct validity of second-session KAE as a measure of need for stimulation. These data do support the KAE as a personality measure but, when contrasted to arguments that only first-session KAE is valid, the data indicate that this is unresolved.     

The kinesthetic fusion effect: Perceptual elimination of spatial discordance in the kinesthetic modality

Three experiments in intrasensory kinesthetic discordance are reported. The treatment required both arms to be outstretched in the midsagittal plane. In the absence of vision, a finger of one hand depressed a button that caused a probe to touch the other arm 12.7 cm closer to the body than the position of the finger. This difference was at first clearly sensed, but very rapidly the disparate positions were perceived to be identical: We have called this “the kinesthetic fusion effect.” It was also shown that a delay of up to 4 sec in probe onset after the finger depressed the button did not diminish the extent of fusion. The phenomenon gave rise to a predictable aftereffect, in which a probe directly opposite to the active finger was sensed to be farther away than the finger. The results were not due either to joint adaptation or to postural aftereffects.     

Induction and retention of kinesthetic aftereffects as a function of number and distribution of inspection trials

Measures of kinesthetic aftereffects were made for 240 Ss in 15 groups. Each group was tested with a combination of number of 30-sec. inspection periods (5, 10, or 15) and time between inspection periods (0, 10, 30, 60, or 90 sec). The number of inspection periods had a significant effect on size of aftereffect and on residual aftereffect 15 min later. The maximum aftereffect followed the 10 period inspection (5 min inspection). Distribution of inspection periods in time had no significant effect on these measures of aftereffect. In a second experiment, distribution of inspection periods in time had no effect on induced aftereffect or on residual aftereffect 24 h later. There was significant residual aftereffect after 24 h which was significantly related to amount of aftereffect originally induced.     

Orientation-specificity in kinesthetic spatial learning: The role of multiple orientations

In the current study we tested whether multiple orientations in kinesthetic learning affected how flexibly spatial information is stored and later used in making location judgments. Three groups learned simple routes by walking them while blindfolded, with (1) multiple orientations achieved through normal walking, (2) multiple orientations achieved through backward walking, or (3) a single orientation achieved through walking without turning (which required forward, backward, and sideways walking). When subjects had experienced multiple orientations while learning the routes, later directional judgments were equally accurate (and equally rapid) regardless of whether the judgments were aligned or were contra-aligned with the orientation of the routes as originally learned. In contrast, when routes were learned in a single orientation (without turning), subsequent judgments on contra-aligned trials were both less accurate and slower than judgments on aligned trials. Thus, multiple orientations are important to establish orientation-free, flexible use of spatial information in a kinesthetic learning environment. This contrasts with the pattern of results typically found in visual spatial learning and suggests that the factors that affect orientation specificity of spatial use may differ across spatial modality.     

The aftereffects of ventriloquism: patterns of spatial generalization

We examined how visual recalibration of apparent sound location obtained at a particular location generalizes to untrained locations. Participants pointed toward the origin of tone bursts scattered along the azimuth, before and after repeated exposure to bursts in one particular location, synchronized with point flashes of light a constant distance to their left/right. Adapter tones were presented straight ahead in Experiment 1, and in the left or right periphery in Experiment 2. With both arrangements, different generalization patterns were obtained on the visual distractor's side of the auditory adapter and onthe opposite side. On the distractor side, recalibration generalized following a descending gradient; practically no generalization was observed on the other side. This dependence of generalization patterns on the direction of the discordance imposed during adaptation has not been reported before, perhaps because the experimental designs in use did not allow its observation.     

Intermittent reinforcement of a continuous response

Konorski showed that when a go/no-go procedure was used, sound quality discriminations were rapidly acquired and sound location discriminations were slowly acquired. These findings have been interpreted as a general constraint on the acquisition of auditory discriminations (quality-location effect). However, experiments carried out within an evolutionary framework (Harrison, 1984) have shown that the rate of acquisition of sound location discriminations varies widely as a function of the inclusion or exclusion of naturalistic features. These data suggest that Konorski's findings were a function of the special conditions of the experiments. The first purpose of the present experiments was to assess whether rats showed the effects noted by Konorski when studied under similar conditions. The second purpose was to study the effect of manipulating two natural features (novelty and stimulus-response adjacency) to assess whether the acquisition rates of quality and location discriminations could be greatly modified or made approximately equal, or both. When a go/no-go procedure was used and the other conditions were similar to those of Konorski, rats acquired a quality discrimination but did not acquire a location discrimination. However, when the S+ or S- were presented through a closely adjacent speaker, the sound location discrimination was acquired as rapidly as the quality discrimination. Finally, preexposing the animal to either S+ or S- retarded the rate of or prevented the acquisition of the quality discrimination. The experiments showed that the quality-location effect was determined primarily by the conditions used in Konorski's experiments, and that the effect is not a general constraint on learning.     

Effectiveness of visual vs kinesthetic instruction for learning a gross motor skill

The purpose of this study was to compare visual with kinesthetic instruction for learning a motor skill that is not visually monitorable. Previous studies comparing visual and kinesthetic information have all used arm tasks for which the nonvisual condition was artificial. 20 subjects were randomly assigned to either a kinesthetic or a visual instruction group. The task was to draw a horizontal line with the right foot while in a quadruped position. All subjects received visual knowledge of results. While performance improved over the course of the 10 instructional sessions and trials, no difference in performance was found between the two instructional groups. A follow-up study is required to determine whether this result was based on visual dominance. Understanding the effectiveness of the different modalities for teaching gross motor skills would be valuable to physical therapists, physical educators, and psychologists.     

Confounding of psychophysical errors and sensory effects in adjustment measures of spatial aftereffects

Measurements of a stereoscopic spatial aftereffect using the method of adjustment without bracketing show that the linear regression of vertical adjustments on starting positions differs between pretests and posttests. The results are given an explanati n in terms of two variables: rapid dissipation of the aftereffect and psychophysical adjustment errors. The implications of the results are discussed.     

Visual dominance in the cross-modal kinesthetic to kinesthetic plus visual feedback condition

In previous studies subjects who have learned a positioning response with kinesthetic feedback tended to make greater errors when visual feedback was provided during later trials. These subjects have always performed with both kinesthetic and visual feedback available. This study determined whether subjects with only visual feedback would produce errors similar to those who received kinesthetic plus visual feedback. Blindfolded subjects learned to move a handle to a criterion location with knowledge of results following each trial. Subjects then were assigned to one of three experimental groups, with only kinesthetic feedback, with kinesthetic plus visual feedback, or with only visual feedback. Subjects had 9 trials without knowledge of results in these feedback conditions. When visual feedback was available, subjects tended to make longer response errors. This finding replicates previous studies. Also, the similarity of performances from the conditions with visual feedback indicated the dominance of visual information in the condition with kinesthetic plus visual feedback.     

The kinesthetic spatial aftereffect as a function of the angular displacement of the joints of the arm

The magnitude of the kinesthetic spatial aftereffect following different angular displacements from the vertical and horizontal planes during stimulation was examined in two experiments using 278 Ss. Both Gibson’s direct and indirect effect were found when angular displacements were away from the vertical, however, a bimodal pattern was observed in both experiments when stimulation was away from the horizontal. An explanation for the interaxial difference cannot be provided by conventional theories and must be sought in a consideration of the structure of the joints which are involved with the production of the aftereffect.     

Insights into the development of face recognition mechanisms revealed by face aftereffects

An important question in person perception is how we acquire the perceptual/cognitive mechanisms that characterize adult expertise. Children's performance on face recognition tests improves dramatically between age 4 and adolescence suggesting that our face recognition system may change during childhood. Yet, the source of this improvement is controversial. In this review, we consider whether changes in the way identity is represented/coded in face space could contribute to this age-related improvement. Face aftereffects have been extensively applied to studying face coding in adults and more recently they have been applied to studying the mechanisms of face coding in children. Face aftereffects are temporary distortions of perception induced by exposure to faces and are thought to reflect the mechanisms underlying face perception. Face aftereffect techniques have revealed that children as young as 4 years of age show evidence of adult-like face space organization, with opponent coding of face dimensions. These findings are consistent with an emerging picture that the key mechanisms of face perception are present early in childhood.     

Location of the egocenter in kinesthetic space

The location of the egocenter in kinesthetic space was investigated in 4 experiments. Participants, with their eyes closed, adjusted a comparison stimulus after or while touching a standard in a transverse plane at the belly or shoulder level so that they perceived the line joining the comparison and the fixed standard as pointing directly at themselves. The mean location of the intersections of the obtained lines was taken as the location of the egocenter. The main results showed that the location of the kinesthetic egocenter depended on the hand or hands used for touching, the timing of touching, and the distance of the standard from the participant. Implications of these results were discussed in relation to models of the kinesthetic egocenter.     

Intermittent stimulation of binocular disparatecolors and central color fusion

Two experiments were conducted to determine the relationships between the various parameters of intermittent stimulation and the occurrence of binocular color fusion. Numerous combinations of on and off durations were presented, some synchronously and some asynchronously. Three Os were asked to report all colors experienced during the 15-sec viewing period. Experiment ] showed that fusion can be reliably obtained with on durations of less than 100 msec in combination with off durations of more than 100 msec. Experiment 2 indicated that the limit of dichoptic onset asynchrony within which color fusion reliably occurs is 25 msec. Two possible alternative hypotheses consistent with the data are discussed.     

Effects and aftereffects of continuous noise and computation work on risk and effort choices

Choices between risk and effort, in a format (COPE) previously shown to reflect fatigue, were obtained from subjects in noise or quiet. Both sexes were used in the experiment, half the subjects working at the Norinder arithmetic task while half rested. The COPE test took a computational form, offering choices between digit lists of differing lengths in which target sums were imbedded. The baseline choice levels were established in quiet, but half the subjects were exposed to noise during the posttest. As previously found in comparable conditions, the Norinder task showed no effect of noise. Pretest-posttest comparisons on the COPE test showed that exposure to noise, like computation work, had the predicted effect of decreasing the choice of high-probability, high-effort alternatives. The presence of noise during posttest had no overall effect on risk effort choices, although there were indications that changes of any kind in the test conditions might be a factor. The data seem difficult to explain in an arousal framework, but may be simply interpreted as showing that exposure to noise produces real fatigue.