Abstract
A pitched visual field influences the perceived elevation of objects within the field and the elevation visually perceived as eye level, VPEL (reviewed in Matin & Li, 2010). In the present report we show that a pitched stationary inducer also produces changes in the perceived direction of motion (no movement of the inducer is involved). Specifically: a stream of water that is physically flowing downhill in a transparent linear tube appears to flow uphill when it is viewed against a stationary topbackward pitched visual field. Data showing the magnitude of the illusion with parametric variation of pitchroom orientation and tube orientation will be presented. At the poster we will provide a demonstration of the illusion with a topbackward pitched visual field that induces a 12o downward displacement of VPEL. We explain the upward direction of perceived water flow by combining two facts: (1) pitching a visual field changes the elevation of VPEL, and (2) the illusory uphill water flow occurs when the tube is set in a surface between the horizontal surface containing true eye level and the surface containing VPEL.
Meeting abstract presented at VSS 2014