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.     

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.     

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.     

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.     

The motion aftereffect

The motion aftereffect is a powerful illusion of motion in the visual image caused by prior exposure to motion in the opposite direction. For example, when one looks at the rocks beside a waterfall they may appear to drift upwards after one has viewed the flowing water for a short period-perhaps 60 seconds. The illusion almost certainly originates in the visual cortex, and arises from selective adaptation in cells tuned to respond to movement direction. Cells responding to the movement of the water suffer a reduction in responsiveness, so that during competitive interactions between detector outputs, false motion signals arise. The result is the appearance of motion in the opposite direction when one later gazes at the rocks. The adaptation is not confined to just one population of cells, but probably occurs at several cortical sites, reflecting the multiple levels of processing involved in visual motion analysis. The effect is unlikely to be caused by neural fatigue; more likely, the MAE and similar adaptation effects provide a form of error-correction or coding optimization, or both.     

The vernier aftereffect

Exposure to a vernier offset can cause a subsequently viewed straight contour to appear offset in the opposite direction. The size of this vernier aftereffect (VAE) varies systematically with the size of the adapting offset. The VAE may be a version of the tilt aftereffect.     

The motion aftereffect reloaded

The motion aftereffect is a robust illusion of visual motion resulting from exposure to a moving pattern. There is a widely accepted explanation of it in terms of changes in the response of cortical direction-selective neurons. Research has distinguished several variants of the effect. Converging recent evidence from different experimental techniques (psychophysics, single-unit recording, brain imaging, transcranial magnetic stimulation, visual evoked potentials and magnetoencephalography) reveals that adaptation is not confined to one or even two cortical areas, but occurs at multiple levels of processing involved in visual motion analysis. A tentative motion-processing framework is described, based on motion aftereffect research. Recent ideas on the function of adaptation see it as a form of gain control that maximises the efficiency of information transmission at multiple levels of the visual pathway.     

Visual tilt normalization: The method of kinesthetic matching

Changes in the apparent tilt of a visual line over time were tracked by matching the orientation of a rod held in the hands. The degree of overestimation of 20-deg tilts diminished over time by about 2 deg. This occurred even though the adaptation line was exposed intermittently with a 1∶3 on/off ratio.     

The funeral meal: A significant funerary ritual

Historically, a meal in association with funerary ritual has been a reality in many cultural and religious settings. Our society has experienced a gradual demise of formal funerary ritual, with an accompanying psychological and social impoverishment. Both the immediate bereaved and the larger social community can benefit from a funeral meal which functions as a group experience that focuses on the needs of the living. It can be a shared experience in a familiar structured setting which enables the living to do significant grief work. Practical implications and potential problems will need to be, taken into consideration.     

The spiral aftereffect and personality

Reported duration of the spiral aftereffect was correlated with scores on the four scales of the Eysenck Personality Questionnaire and with the Psychoticism (P) scale from the unpublished PEN Inventory. There was a strong positive correlation between PEN P and duration. None of the other correlations approached statistical significance.     

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.