Equivalence of physical and perceived speed in binocular rivalry

Abstract

The relative dominance of gratings engaged in binocular rivalry can be influenced by their surroundings. One striking example occurs when surrounding motion is congruent with one but not the other grating (C. L. Paffen, S. F. te Pas, R. Kanai, M. J. van der Smagt, & F. A. Verstraten, 2004). However, such center-surround stimulus configurations can also modulate perceived speed, via a directionally tuned process (H. P. Norman, J. F. Norman, J. T. Todd, & D. T. Lindsey, 1996). We recorded rivalry for Gabor patches embedded in a drifting noise texture. Gratings whose directions opposed the background motion tended to dominate more, and vice versa, consistent with previous findings. Observers then matched the speed of a drifting noise-embedded Gabor to that of a Gabor surrounded by mean luminance. Surround motion produced substantial changes in perceived speed, by at least a factor of two for all observers. We then asked whether perceived speed could account for the contextual effects on dominance. We measured the effects of speed on rivalry dominance by changing the physical speeds of rivaling gratings, as determined by the matching data. We found the same pattern of dominance as for the context experiment, indicating that perceived and true speed influence rivalry in the same manner. We propose a Bayesian interpretation of the perceived speed illusion.

Natural images dominate in binocular rivalry

“…When stimuli are defined by spatial form but also have a temporal component, rivalry is usually possible provided the temporal frequencies are similar (42,43). Over a limited range, faster stimuli will dominate over slow or static stimuli (44)(45)(46)(47). However, this is by no means a general property; for some dichoptic motion combinations, faster stimuli are less dominant (46).…”

“…Other image properties can play a major role in binocular rivalry. Contextual information in many domains, including color (54,55), global motion (56), surround orientation (55,57,58), surround motion (47,59), percept history (60), and depth information (61), can also influence the pattern of dominance during rivalry in a variety of ways. Furthermore, it has been demonstrated that coherent visual objects, such as houses or faces, produce deeper rivalry suppression with more global (and fewer piecemeal) alternations, compared with simple grating stimuli (34).…”

Contextual effects in speed perception may occur at an early stage of processing

“…The data shown in Figure 1 are replotted fromBaker&Graf Figure3therein) and illustrate the phenomena and stimuli used. Baker & Graf (2008). Perceived speed was measured using a speed matching task, for a range of surround directions, and is shown for three observers (symbols) and their average (line).…”

“…Perceived speed was measured using a speed matching task, for a range of surround directions, and is shown for three observers (symbols) and their average (line). Methodological details are given in Baker &Graf(2008).Notethatourstudyusedacentral grating stimulus surrounded by a noise texture (see inset), whereas most previous studies had used dot motion. The physical speed of both centre and surround was always 0.5deg/sec (dashedline).…”

Comparative Research of Visual Interpretation of Aerial Images and Topographic Maps for Unskilled Users: Searching for Objects Important for Decision-Making in Crisis Situations

“…Although airplanes capture land from a bird's eye perspective as well as maps, they are more readable for children than maps, especially because it is a real representation of the landscape, while map depicts individual elements using different symbols [7]. With increasing age, the ability to find and identify objects and stimuli worsens [8,9], reaction time increases [10,11]; perception of space, orientation and navigation deteriorates [12].…”