When human observers are shown a horizontally moving target which suddenly disappears and they are further instructed to locate its vanishing position, both forward in the direction of motion (M Displacement) and downward in the direction of gravity (O Displacement), errors of localization typically occur. Though several determinants of those errors have been ascertained, little is known regarding their time course. The present study attempts to fill this gap. Horizontally moving targets were presented and participants instructed to locate their vanishing position, either via a mouse or a pointer (on a touch screen) after a variable time delay. Outcomes revealed an orderly time-dependent trajectory of errors being describable in two stages - during the first 300ms, the errors increased in the direction of motion with a constant vertical error; after 300ms the downward error increased with no further horizontal displacement. Similarities between this pattern and reported results from the Intuitive Physics (Road Runner Physics) and the History of Ancient Physics are noticed and discussed under the notion of an implicit representation of physical invariants in the perception of dynamic events.
Motion perception; Intuitive Physics; representational momentum; representational gravity
