Visually and memory-guided grasping: aperture shaping exhibits a time-dependent scaling to Weber's law.

摘要: The ‘just noticeable difference’ (JND) represents the minimum amount by which a stimulus must change to produce variation in one’s perceptual experience and is related initial magnitude (i.e., Weber’s law). goal of present study was determine whether aperture shaping for visually derived memory-guided grasping elicit temporally dependent or independent adherence law. Participants were instructed grasp differently sized objects (20, 30, 40, 50 60 mm) conditions wherein vision environment available throughout response closed-loop), when occluded at movement onset open-loop), brief 0 ms) longer 2000 delay advance onset. Within-participant standard deviations grip JNDs) computed decile increments normalized time used participant’s sensitivity detecting changes object size. Results showed that JNDs increased linearly with increasing size from 10% 40% time; is, trial-to-trial stability visuomotor certainty) comparator) decreased stimulus). However, null JND/object scaling observed during middle late stages >50% time). Most notably, temporal relationship between similar across different visual here. Thus, our results provide evidence elicits time-dependent early, but not late, psychophysical principles