Two orthogonal patterns presented to the two eyes, respectively, are percei
ved as alternating in time, a phenomenon often assumed to reflect competiti
on between neuronal activities corresponding to the two eyes, presumably in
the primary visual cortex. Recent evidence supports a competition between
neuronal activities corresponding to the two patterns (objects) at some hig
her cortical processing stage after inputs from the two eyes have converged
. Here, using textures made of Gabor signals, we present psychophysical dat
a showing that the level of visual processing at which competition takes pl
ace and is resolved, is determined by the degree of stimulus coherence. Mor
eover, depending on stimulus parameters, competition may occur at several l
evels of processing at the same time. (C) 2001 Elsevier Science Ltd. All ri
ghts reserved.