Visual space orientation and representational gravity: orientation polarizing visual cues modulate the perceptual extrapolation of motion

• Autor(a) principal: Freitas, Rodrigo Ribeiro
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/32042
• topic: Spatial orientation; Motion perception; Subjective visual vertical; Perceptual upright; Representational momentum; Representational gravity

The perceived offset of a moving target is usually displaced forward, in the direction of motion (Representational Momentum), and downwards, in the direction of gravity (Representational Gravity). In what refers to the latter, the meaning of “downward in the direction of gravity” is ill-defined, for it is known that the perceived direction of gravity (“downward”) results from the interaction of vestibular signals, sensitive to the gravito-inertial vector, an aprioristic tendency to assume that it aligns with the body’s main axis (idiotropic vector) and visual cues. The present work aims to disclose what effects visual cues have on Representational Gravity. Participants performed a spatial localization task as well as a Subjective Visual Vertical (SVV) and an Oriented Character Recognition Task (OCHART), with stimuli being presented above a realistic background either aligned with earth’s vertical or tilted rightward or leftward. Outcomes disclosed significant and lawful effects of the orientation of the visual context on spatial localization judgements. Specifically, forward displacement along the target’s motion direction (M-displacement) was bigger for targets moving along the ‘horizontal’ direction implied by the background scene. These trends were furthermore found to be correlated, at an individual level, with the magnitude of SVV, but not of the Perceptual Upright (as measured with OCHART). These findings show that features of the spatial localization judgements specifically index the visually induced spatial orientation, thus offering the prospect to expand available tools for inquiries concerning human spatial orientation, besides clarifying the multisensorial nature and significantly expanding the notion of Representational Gravity.