Vernier offset produced by rotary target motion

Two separated colinear lines appear displaced from colinearity when either the target or the subject’s head is rotated in a frontal plane. The direction of perceived offset is reversed for opposite directions of rotation. The present experiments prove that the effect depends on some property of the visual system that is responsive to stimulus motion per se and is not manifested in the response to stationary targets. Two mechanisms which may be responsible for the rotation-contingent effect are considered: (1) An induction mechanism based on the dynamics of induced tilt or of figural aftereffect displacement. (2) A mechanism based on variation of visual latency with stimulus energy/time.     

Misinterpretation of instructions in an aftereffect task

Some subjects in studies of kinesthetic aftereffect erroneously believe the task is to show the width of the aftereffect inducing rather than the standard stimulus. Although such subjects may be encountered rarely, the errors they make are very large. Precautionary steps are indicated.     

Effects of mental imagery styles on shoulder and hip rotations during preparation of pirouettes

To analyze individual behavior in spatial navigation especially for pirouette preparations (complete whole-body rotations), the authors studied horizontal shoulder-hip interactions under 2 constraints: postural (right and left supporting legs [SL]) and spatial (clockwise [CW] and counterclockwise [CCW]). They performed kinematic analysis at the start and end of the shoulder-hip horizontal rotations (run-up) with regard to imagery of motor actions. On the basis of the Vividness of Movement Imagery Questionnaire, they classified 8 female expert ballet dancers and 7 untrained female participants according to their movement imagery style (kinesthetic and visual). At the run-up's end, the shoulders initiated the turn independently of SL but differently depending on training: CW for dancers and CCW for untrained participants (their commonly used direction). Kinesthetic and mixed imagery styles prevailed in dancers, whereas simply a mixed style appeared among untrained participants. Thus, dance training enhances the imagery of kinesthetic sensation and influences the choice of spatial direction, facilitating the body-space interaction.     

A further investigation of apparent size and retinal size as determinants of the figural after-effect

A figure which is more distant from the eye than another but subtends the same visual angle is usually seen as the larger. This phenomenon is called perceptual size constancy. Experiments have been reported which show that sometimes the apparent and sometimes the retinal sizes of the stimulus figures determine the direction of the figural after-effect. These experiments are reviewed and two further experiments are reported. In the first experiment two types of stimulus figure (discs and annuli) which subtended a visual angle of 1° 36' resulted in figural after-effects, the direction of which would have been predicted by the retinal sizes of the figures. In the second experiment larger figures were used which subtended a visual angle of about 4° and which were the same as those used by Sutherland (1954). In this experiment the after-effects were generally in a direction which would have been expected if apparent size determined the direction of the after-effect. In the interpretation of the results attention is drawn to the “Central Tendency Effect” which has been observed in size judgements of stimulus figures of varying size. Two hypotheses are suggested; one is that the true figural aftereffect has been obscured by the “Central Tendency Effect” in successive judgements, and the other is that time error in successive judgements of size is essentially a figural aftereffect. Some supportive evidence for the latter hypothesis is reported. It is concluded that apparent size is not a critical determinant of the figural after-effect.     

PERSONALITY AND DRUGS IN VISUAL FIGURAL AFTEREFFECTS

The effects of dexedrine and phenobarbitone on visual figural aftereffect (VFAE) were examined in 32 postgraduate students selected after a preliminary testing with the Maudsley Personality Inventory. Calcium tablets were used as placebos. The subjects were repeatedly tested under each of the treatment conditions. The results supported the following conclusions: (1) extraverted subjects relative to introverted ones had larger VFAE; (2) the size of VFAE increased under the influence of phenobarbitone in all personality groups except N+E+ and N-E-; (3) interactions between the drug treatments and personality variables in effects on VFAE did not occur.     

Induction-, test-, and comparison-figure interactions under illusion and figural aftereffect conditions

Ganz (1966a, b) has argued that an induction figure will displace a test figure placed near it under both illusion and figural aftereffect conditions. The data from Experiments I and II show that most of the illusion produced by the figures studied by Ganz results from an interaction between the comparison and induction figures. The data from Experiment III suggest that both the test and comparison figures interact with the induction figure under figural aftereffect conditions. Although the induction-test figure interactions do not contradict Ganz’s model, the induction-comparison figure interactions cannot be explained by it. The data also suggest that researchers should be extremely cautious in drawing conclusions about the processes underlying illusions and figural aftereffects unless they are confident that there is no interaction between the induction and comparison figures.     

The psychophysics of the kinesthetic aftereffect in the Petrie block experiment

Kinesthetic size is reported in the Petrie experiment by a simultaneous size comparison in which a standard block held between the thumb and forefinger of one hand is matched in size by moving the thumb and forefinger of the opposite hand along a wedge until the proper width is reached. After a baseline is obtained, a kinesthetic aftereffect is produced by rubbing a block of contrasting size followed by a return to the standard block. Experiments with 22 male Ss and 20 female Ss, tested in separate cycles, show that augmentation following stimulation with a block smaller than standard and reduction following stimulation with a block larger than standard are both statistically significant, and, at least for augmentation, the aftereffect persists for at least 48 h. When the data are corrected for regression there is no significant relationship between initial baseline and the amount of augmentation or reduction; reasons why such a relationship has been reported are indicated. The results suggest that when this kind of experiment is used for the study of individual differences (a) it is satisfactory to derive augmentation and reduction scores by subtracting the baseline from the absolute scores, provided the scores are corrected for regression, and (b) a counterbalanced order of presentation is not advisable in view of the carryover of augmentation from one day to the next, which is likely to make the two orders incommensurate.     

Inter-individual neural differences in movement imagery abilities

ObjectivesBuilding on mounting evidence distinguishing the neurological basis of different movement imagery abilities (visual versus kinesthetic), this study compared brain activity (i.e., blood flow changes) through functional magnetic resonance imaging elicited by movement imagery in participants self-reporting good and poor imagery abilities with the Movement Imagery Questionnaire-3. Participants also completed the Vividness of Movement Imagery Questionnaire-2. Method: Thirty-seven females (good imagery ability = 18; poor imagery ability = 19) were randomly presented with four experimental conditions (i.e., Kinesthetic, Internal Perspective, External Perspective and Rest) counterbalanced for condition, during three separate 11-min functional brain scans. Results: Kinesthetic and visual (internal/external) subscale mean differences of the Vividness of Movement Imagery Questionnaire-2 favored good imagers and high Movement Imagery Questionnaire-3 inter-scale correlations evidenced convergent validity. As in prior published work, kinesthetic, internal, and external visual imagery elicited distinct patterns of brain activation relative to rest. Overall, the patterns of brain activity in the good and poor imager groups were remarkably similar, indicating that they both generally relied on a similar brain network during movement imagery. Conclusions: Contrary to processing efficiency hypotheses (i.e., neural efficiency hypothesis) we report that during kinesthetic imagery and external visual imagery only, good imagers actually activated a greater number of spatially distinct cortical sites than did poor imagers. Furthermore, research is needed to fully characterize the neural signature of movement imagery in good and poor imagers. Such research is critical to the appropriate creation and proper application of neuroscience-inspired movement imagery-based learning interventions in healthy and clinical populations.     

Systematic changes in perceptual reactance induced by physical fitness training

The effect of life-change events on perceptual augmentation-reduction was studied in 72 subjects (40 men, 32 women). In three experiments the kinesthetic figural aftereffect was measured prior to and after either a physical fitness program, a course in yoga, or training in Transcendental Meditation. Each program lasted a minimum of 8 wk. Subjects completing fitness training, all of whom were initially classified as augmenters, became reducers by the end of their program. Subjects enrolled in yoga and meditation courses remained relatively stable in their perceptual tendencies.     

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.     

The role of interpersonal movement synchronisation in empathic functions: Insights from Tango Argentino and Capoeira

Although evidence points to a role for kinesthetic empathy (i.e. spontaneous interpersonal movement imitation and synchronisation) in social interaction, its relationship with emotional and cognitive aspects of empathy is unknown. We compared empathy in Tango and Capoeira experts, which crucially depend on ongoing, mutual interpersonal synchronisation, with empathy in practitioners of Salsa and Breakdance, respectively, which demand less interpersonal synchronisation but are comparable concerning movements and setting. Kinesthetic empathy was increased in the Tango and Capoeira groups. Although no group differences in other aspects of empathy were detected, kinesthetic empathy correlated with emotional and cognitive empathy. Taken together, trait kinesthetic empathy varies in the general population, and appears increased in synchronisation experts.     

Time-dependent effects of kinesthetic input

Sensory input can be used by the nervous system to control the spatial parameters of motor responses (e.g., distance, velocity, and direction) by initializing these parameters before movement onset and then by adjusting these parameters during movement. Sensory input can also be used to trigger movements. In the experiments reported in this paper, we compared the effects of kinesthetic input on a triggered motor response when the kinesthetic input was generated at different times relative to the onset of the motor response. Human subjects responded to a visual stimulus by intentionally increasing elbow torque to a target level. Kinesthetic input was generated by unexpectedly rotating each subject's elbow 100 ms before the onset of the intentional torque response (early) or coincident with the onset of the intentional torque response (late). The effect of early kinesthetic input on the intentional torque response markedly differed from the effect of late kinesthetic input. The effect of early kinesthetic input was relatively independent of the direction of elbow rotation, had a different dependence on the amplitude of rotation, and required a shorter duration of rotation compared to the effect of late kinesthetic input. These differences in the effects of early and late kinesthetic input might be related to the initialization, triggering, and adjustment of motor responses.     

Relationship between upper extremity kinesthetic sense and writing performance by students with low vision

Kinesthetic sense plays an important role in writing. Children with low vision lack sensory input from the environment given their loss of vision. This study assessed the effect of upper extremity kinesthetic sense on writing function in two groups, one of students with low vision (9 girls and 11 boys, 9.4 +/- 1.9 yr. of age) and one of sighted students (10 girls and 10 boys, 10.1 +/- 1.3 yr. of age). All participants were given the Kinesthesia Test and Jebsen Hand Function Test-Writing subtest. Students with low vision scored lower on kinesthetic perception and writing performance than sighted peers. The correlation between scores for writing performance and upper extremity kinesthetic sense in the two groups was significant (r = -.34). The probability of deficiencies in kinesthetic information in students with low vision must be remembered.     

Menstrual cycle affects kinesthetic aftereffect, an index of personality and perceptual style

Research suggests that kinesthetic aftereffect (KAE) scores reflect status on a postulated stimulus intensity modulation (SIM) mechanism that damps down subjective stimulus intensity for some (reducing) and increases it for others (augmenting). Such a mechanism would help account for empirically observed individual differences in such behaviors as pain tolerance, sensory deprivation reactivity, and stimulation seeking. It was hypothesized and confirmed in three adult female samples that KAE varies curvilinearly over the menstrual cycle: Greater KAE reduction occurs at the cycle's beginning and end. Neither tiredness, oral contraception, medication, attention, nor social expectations can explain this finding. Of the behaviors studied in the KAE literature, only five are also encompassed by the menstrual cycle literature. Four of these (antisocial behavior, acute schizophrenic episodes, accidents, and activity level) show similar curvilinearity over the cycle. We hypothesize that cyclical variation in the SIM mechanism mediates the curvilinear pattern observed for both these four behaviors and KAE.     

EYEMOVEMENT AND PERCEPTUAL ADAPTATION TO CURVATURE

It is proposed that perceptual adaptation is basically an immediate localized consequence of stimulation but can become generalized through a process of conditioning by temporal contiguity. Experimental conditions were designed to assess the aftereffect of adaptation to curvature under various combinations of eye position and eye movement activity for adapting vs. test periods. In general, the results support the hypothesis that perceptual adaptation to a visual stimulus can be associated with the nonvisual factors present at the time the adaptation occurs.     

Atypical updating of face representations with experience in children with autism

Face identity aftereffects are significantly diminished in children with autism relative to typical children, which may reflect reduced perceptual updating with experience. Here, we investigated whether this atypicality also extends to non‐face stimulus categories, which might signal a pervasive visual processing difference in individuals with autism. We used a figural aftereffect task to measure directly perceptual updating following exposure to distorted upright faces, inverted faces and cars, in typical children and children with autism. A size‐change between study and test stimuli limited the likelihood that any processing atypicalities reflected group differences in adaptation to low‐level features of the stimuli. Results indicated that, relative to typical children, figural aftereffects for upright faces, but not inverted faces or cars, were significantly attenuated in children with autism. Moreover, the group difference was amplified when we isolated the ‘face‐selective’ component of the aftereffect, by partialling out the mid‐level shape adaptation common to upright and inverted face stimuli. Notably, the aftereffects of typical children were disproportionately larger for upright faces than for inverted faces and cars, but the magnitude of aftereffects of autistic children was not similarly modulated according to stimulus category. These findings are inconsistent with a pervasive adaptive coding atypicality relative to typical children, and suggest that reduced perceptual updating may constitute a high‐level, and possibly face‐selective, visual processing difference in children with autism.     

Timing for the absence of a stimulus: the gap paradigm reversed

Contrary to data showing sensitivity to nontemporal properties of timed signals, current theories of interval timing assume that animals can use the presence or absence of a signal as equally valid cues as long as duration is the most predictive feature. Consequently, the authors examined rats' behavior when timing the absence of a visual or auditory stimulus in trace conditioning and in a "reversed" gap procedure. Memory for timing was tested by presenting the stimulus as a reversed gap into its timed absence. Results suggest that in trace conditioning (Experiment 1), rats time for the absence of a stimulus by using its offset as a time marker. As in the standard gap procedure, the insertion of a reversed gap was expected to "stop" rats' internal clock. In contrast, a reversed gap of 1-, 5-, or 15-s duration "reset" the timing process in both trace conditioning (Experiment 2) and the reversed gap procedure (Experiment 3). A direct comparison of the standard and reversed gap procedures (Experiment 4) supported these findings. Results suggest that attentional mechanisms involving the salience or content of the gap might contribute to the response rule adopted in a gap procedure.     

Why do temporal generalization gradients change when people make decisions as quickly as possible?

Three experiments investigated temporal generalization performance under conditions in which participants were instructed to make their decisions as quickly as possible (speed), or were allowed to take their time (accuracy). A previous study (Klapproth & Müller, 2008) had shown that under speeded conditions people were more likely to confuse durations shorter than the standard with the standard than in the accuracy conditions, and a possible explanation of this result is that longer stimulus durations are "truncated" (i.e., people make a judgement about them before they have terminated, thereby shortening their effective duration) and that these truncated durations affect the standard used for the task. Experiment 1 investigated performance under speed and accuracy conditions when comparison durations were close to the standard or further away. No performance difference was found as a function of stimulus spacing, even though responses occurred on average before the longest durations had terminated, but this lack of effect was attributed to "task difficulty" effects changing decision thresholds. In Experiment 2, the standard duration was either the longest or the shortest duration in the comparison set, and differences between speed and accuracy groups occurred only when the comparisons were longer than the standard, supporting the "truncation" hypothesis. A third experiment showed that differences between speed and accuracy groups only occurred if some memory of the standard that was valid for more than one trial was used. In general, the results suggest that the generalization gradient shifts in speeded conditions occur because of truncation of longer comparison durations, which influences the effective standard used for the task.     

The perception of verticality and the frame of reference of the visual tilt aftereffect

Previous research has suggested that the visual tilt aftereffect operates according to a gravitational frame of reference. Three experiments were conducted to test this conclusion further. In each experiment, observers (with head upright) adjusted an illuminated bar to apparent vertical following various adaptation conditions. In Experiment 1, observers were given clear visual cues for objective vertical while adjusting the bar. In Experiment 2, they were not given visual cues for vertical. The adaptation conditions in Experiments 1 and 2 consisted of various combinations of head and stimulus tilt. Experiment 3 investigated the effects of head tilt alone. The results indicated that the tilt aftereffect follows a retinal frame of reference under some conditions (Experiment 1) and appears to follow a gravitational frame under others (Experiment 2). These results can be predicted by a simple model involving two factors, a purely visual aftereffect that follows a retinal frame and an extravisual aftereffect that appears to follow a gravitational frame.     

Mystery of the anti-McCollough effect

The McCollough Effect (ME) is a complex perceptual aftereffect that remains of interest half a century after its discovery. It is argued that a recently reported variant, dubbed the anti-McCollough effect, is not the reverse of the ME, with aftereffect colors in the same direction as the inducing stimuli. A red-horizontal stimulus leads to a reddish aftereffect not because of red-horizontal parings, but despite them. The anti-ME is a weak standard-direction ME produced by complementary afterimage colors (afterimage green with horizontal), rather than by environmental colors, first shown decades ago. It is not a new type of contingent aftereffect. The red-horizontal pair does not interfere with the afterimage green-horizontal pair it produces because a single color-orientation pairing provides more ambiguous input than does the standard two orientation-color pairings (red-horizontal, green-vertical) of the ME. It is also argued that not even one orientation-contingent color aftereffect is convincingly shown in the "anti"-ME, let alone, as has previously been suggested, two simultaneous orientation-contingent color aftereffects in opposite directions at different levels of the visual system, in which the higher-level effect suppresses the downstream effect from reaching consciousness. The "anti"-ME can be explained by existing theories of contingent aftereffects, including perceptual-learning theory.