Influence of viewing distance on aftereffects of moving random pixel arrays.
Viewing-distance invariance of visual perception has evolutionary advantages, but it is of necessity limited by spatial and temporal resolution. Even within these resolution limits viewing-distance invariance might not be perfect or even good, but there are remarkably few studies of its precise limits. Here we ask to what extent viewing-distance invariance holds for motion aftereffects (MAEs). There are (at least) two different MAEs: one can be seen on a static test pattern (sMAE) and is tuned to low speeds, the other only becomes manifest on a dynamic noise test stimulus (dMAE) and is sensitive to higher adaptation speeds. We show that each of these MAEs has a limited viewing-distance invariance, the dMAE only for higher screen-speeds and the sMAE only for lower screen-speeds. In both cases upper angular-speed limits shift to higher values for smaller viewing-distances (lower spatial frequencies, larger fields). This upper limit is constant, independent of viewing distance, if expressed in terms of screen-speed. On the other hand the lower speed limit is fixed in angular-speed and variable in screen-speed terms. Explanations for these findings are provided. We show that there is no fixed optimum viewing-distance or optimum angular stimulus-size for either of the two MAEs.
van de Grind
Wim A
WA
Functional Neurobiology and Helmholtz Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. w.a.vandegrind@bio.uu.nl
Verstraten
Frans A J
FA
van der Smagt
Maarten J
MJ
D003196:Computer Graphics; D004215:Distance Perception / Q000502:physiology*; D005366:Figural Aftereffect; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D011601:Psychophysics