Observers typically present a strong bias in estimating the orientation of a visual bar when their body is tilted >60° in the roll plane and in the absence of visual background information. Known as the A-effect, this phenomenon likely results from the under-compensation of body tilt. Static visual cues can reduce such bias in the perceived vertical. Yet, it is unknown whether dynamic visual cues would be also effective. Here we presented projectile motions of a visual target along parabolic trajectories with different orientations relative to physical gravity. The aim of the experiment was twofold: First, we assessed whether the projectile motions could bias the estimation of the perceived orientation of a visual bar, measured with a classical subjective visual vertical (SVV) task. Second, we evaluated whether the ability to estimate time-to-contact of the visual target in an interception task was influenced by the orientation of these parabolic trajectories. Two groups of participants performed the experiment, either with their head and body tilted 90° along the roll plane or in an upright position. We found that the perceived orientation of the visual bar in the SVV task was affected by the orientation of the parabolic trajectories. This result was present in the tilted but not in the upright participants. In the interception task, the timing error increased linearly as a function of the orientation of the parabola. These results support the hypothesis that a gravity vector estimated from dynamic visual stimuli contributes to the subjective visual vertical.

Balestrucci, P., Maffei, V., Lacquaniti, F., Moscatelli, A. (2021). The effects of visual parabolic motion on the subjective vertical and on interception. NEUROSCIENCE, 453, 124-137 [10.1016/j.neuroscience.2020.09.052].

The effects of visual parabolic motion on the subjective vertical and on interception

Balestrucci, Priscilla
;
Lacquaniti, Francesco
Conceptualization
;
Moscatelli, Alessandro
2021-01-01

Abstract

Observers typically present a strong bias in estimating the orientation of a visual bar when their body is tilted >60° in the roll plane and in the absence of visual background information. Known as the A-effect, this phenomenon likely results from the under-compensation of body tilt. Static visual cues can reduce such bias in the perceived vertical. Yet, it is unknown whether dynamic visual cues would be also effective. Here we presented projectile motions of a visual target along parabolic trajectories with different orientations relative to physical gravity. The aim of the experiment was twofold: First, we assessed whether the projectile motions could bias the estimation of the perceived orientation of a visual bar, measured with a classical subjective visual vertical (SVV) task. Second, we evaluated whether the ability to estimate time-to-contact of the visual target in an interception task was influenced by the orientation of these parabolic trajectories. Two groups of participants performed the experiment, either with their head and body tilted 90° along the roll plane or in an upright position. We found that the perceived orientation of the visual bar in the SVV task was affected by the orientation of the parabolic trajectories. This result was present in the tilted but not in the upright participants. In the interception task, the timing error increased linearly as a function of the orientation of the parabola. These results support the hypothesis that a gravity vector estimated from dynamic visual stimuli contributes to the subjective visual vertical.
2021
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore BIO/09 - FISIOLOGIA
English
Con Impact Factor ISI
gravity perception
linear mixed models
subjective visual vertical
Balestrucci, P., Maffei, V., Lacquaniti, F., Moscatelli, A. (2021). The effects of visual parabolic motion on the subjective vertical and on interception. NEUROSCIENCE, 453, 124-137 [10.1016/j.neuroscience.2020.09.052].
Balestrucci, P; Maffei, V; Lacquaniti, F; Moscatelli, A
Articolo su rivista
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/262200
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