Distortions of visual time induced by motor adaptation.

Abstract

Humans and other animals are able to make rough estimations of quantities using what has been termed the approximate number system (ANS). Much evidence suggests that sensitivity to numerosity correlates with symbolic math capacity, leading to the suggestion that the ANS may serve as a start-up tool to develop symbolic math. Many experiments have demonstrated that numerosity perception transcends the sensory modality of stimuli and their presentation format (sequential or simultaneous), but it remains an open question whether the relationship between numerosity and math generalizes over stimulus format and modality. Here we measured precision for estimating the numerosity of clouds of dots and sequences of flashes or clicks, as well as for paired comparisons of the numerosity of clouds of dots. Our results show that in children, formal math abilities correlate positively with sensitivity for estimation and paired-comparisons of the numerosity of visual arrays of dots. However, precision of numerosity estimation for sequences of flashes or sounds did not correlate with math, although sensitivities in all estimations tasks (for sequential or simultaneous stimuli) were strongly correlated with each other. In adults, we found no significant correlations between math scores and sensitivity to any of the psychophysical tasks. Taken together these results support the existence of a generalized number sense, and go on to demonstrate an intrinsic link between mathematics and perception of spatial, but not temporal numerosity.

Duration Selectivity in Right Parietal Cortex Reflects the Subjective Experience of Time

“…Some researchers have proposed that duration channels are located in early processing stages given psychophysical evidence showing that duration aftereffects exhibit modality ( Heron et al, 2012 ; Li et al, 2019 ) and, with visual stimuli, some degree of spatial specificity ( Fulcher et al, 2016 ; see also Johnston et al, 2006 ). In contrast, a later-stage hypothesis is supported by studies showing that the aftereffects in the perceived duration of visual stimuli lack orientation ( Li et al, 2015b ) and position specificity ( Li et al, 2015a ; see also Burr et al, 2007 ; Anobile et al, 2019 ). The right SMG locus observed in the present study would be more consistent with the later-stage account.…”

A Sensorimotor Numerosity System

“…The same reference frame describes selectivity in blind adult participants (square symbols). Reproduced, with permission: (A-D) [57,66], (E) [58], and (F) [6,57,66]. subsequent study [58] characterized better the spatial selectivity of motor adaptation (perceptive field), showing that for both simultaneous and sequential numerosity, adaptation was restricted to an area of radius 12°around the adapted region ( Figure 3E).…”

“…One measured the perceived duration of peripherally presented drifting gratings after tapping quickly or slowly for a few seconds ( Figure 4A). As with numerosity, fast tapping caused a substantial underestimation of the perceived duration of the stimulus presented in the motorically adapted region, while slow tapping expanded the perceived duration ( [58]; Figure 4B,E). Again, the selectivity was in real-world coordinates.…”

“…However, this is not the case. Motion perception (the first reported visual aftereffect [47]) was not affected by motor adaptation [58]: the perceived speed of drifting gratings remained veridical after extensive periods of hand tapping ( Figure 4C). This result suggests that the motor-sensory interactions are specific for representations of the magnitudes time, space, and numerosity, rather than acting on all perceptual attributes.…”

“…(G,H) Motor adaptation on average compressed the perceived spatial separation of about 0.13°, an effect of about 3%. Reproduced, with permission: (A-E) [58] and (F-H) [73].…”