Adaptation to curvature distortion.

Abstract

Two experiments explored some implications of the idea that the visual perception of contour is determined by the efferent readiness activated by the visual input. The 5"s wore prisms on a contact lens, and visual adaptation to the prismatically induced .curvature was measured. The following findings are reported: (a) There is more adaptation and aftereffect with saccadic eye movements than with smooth tracking eye movements; (&) after saccadic eye movements, interocular transfer of aftereffects is greater than 70%; (c) the same results are obtained whether the eye fixates one point or moves freely during measurement; (d) there is evidence for conditional cumulative effects over a series of days.

Alternating prism exposure causes dual adaptation and generalization to a novel displacement

“…This "premature" adaptive behavior is perhaps best conceptualized as conditioned adaptation (e.g., Kravitz, 1972), in which the predictive stimulus (e.g., removal or replacement of the prism goggles) elicits the adaptive response. Evidence of this form of dual adaptation has been obtained as an incidental and often-ignored result of a variety of studies of adaptation to optical rearrangement, in which subjects were used as their own controls in several conditions, separated by days or weeks (Festinger, Burnham, Ono, & Bamber, 1967;Gonshor & Melvill Jones, 1976;Hein, 1972;Klapp, Nordell, Hoekenga, & Patton, 1974;Lackner & Graybiel, 1982;Lackner & Lobovits, 1977;McLaughlin & Webster, 1967;Slotnick, 1969;Welch, Choe, & Heinrich, 1974;Wooster, 1923).…”

Relative mislocalization of briefly presented stimuli in the retinal periphery

“…In that case, any position of a perceived target and of an indicator used for judging the position of targets should be subject to distortion and should, therefore, remain unnoticeable. In addition, central compensations for imperfections of the optic apparatus are well known and include eccentric refractions as well (see, e.g., Erkelens, Collewijn, & Steinman, 1989;Festinger, Burnham, Ono, & Bamber, 1967;Slotnick, 1969). Since the system is able to adapt to such imperfections (cf.…”

Impact of oculomotor retraining on the visual perception of curvature.

“…These curvatures, however, are definitely not very large; there is probably no study in which the retinal curvature was greater than the smallest curvature used in the present experiment, namely, a deviation of 16.8 minutes of arc at a distance of 5° from the center. Festinger et al's (1967) and Slotnick's (1969) contact lens studies produced curvatures of only between 5 and 10 minutes of arc (measures we obtained on the same curvanometer used in those studies). Thus, reports of 30% or 40% adaptation represent perceptual change of only a few minutes of arc, quite comparable to the perceptual changes that we found.…”

“…After 40 minutes of free eye movements scanning the line, there was an average of 44% adaptation when the line was physically straight (and therefore retinally curved) and 18% adaptation when the line was set so that the retinal image was straight (i.e., physically curved). Slotnick (1969), repeating this study with some additional conditions, re-ports very similar amounts of adaptation, namely, 36% and 16%. It seems clear that one obtains some visual perceptual change with no experience other than eye movements when these movements, to be accurate, must conform to the physical relative locations rather thati the discrepant retinal relative locations.…”