The stimuli used in the present study demonstrate that there exist significant global determinants of suppression in (monocular) PR. As mentioned, relatively few stimuli give rise to complete suppression in PR, although partial suppression and alternation of “emphasis” are easily demonstrable with more arbitrary overlapping patterns (e.g.,
Figure 4D can give the impression of subtle changes in the “saliency” or even depth ordering of two superimposed objects without leading to proper PR). BR, although sharing a number of properties with PR, stands in distinction on these points. Perceptual suppression can arise when virtually any pair of dissimilar stimuli are shown to corresponding regions of the two eyes. Also, the depth of suppression during BR is generally complete (i.e., one of the stimuli is completely invisible at each point in space, without transparency), but its expression is often as a mixed patchwork of dominance between the competing stimuli, typically described as piecemeal (e.g. Blake, O'Shea, & Mueller,
1992). Thus, although global configural factors are known to impact BR as well, perception tends to resolve the conflict in circumscribed (i.e., local) zones of dominance. Careful measurements have demonstrated that, at least for many commonly used stimulus types, these zones extend roughly 1° from the site of conflict (Blake et al.,
1992; Kaufman,
1963; O'Shea, Sims, & Govan,
1997). In the present experiments, windows exceeding 4° in diameter were consistently and uniformly suppressed. It may be informative that such suppression was contingent upon there being strict continuity in the pattern (i.e., stripes) between the window and the surrounding region. This requirement for “good continuity” is suggestive that Gestalt-type principles play a role in the determining what is suppressed. This and other observations, such as the role of depth ordering in suppression, are consistent with the notion that conflict resolution in PR is fundamentally a problem of perceptual organization rather than of exclusively peripheral origin. Although the induction and extent of suppression of BR alternation might be more locally restricted than in PR (Carlson & He,
2004), the global context of a scene alters BR alternation as well (e.g., Alais & Blake,
1998,
1999; Alais, O'Shea, Mesana-Alais, & Wilson,
2000; Fukuda & Blake,
1992; Paffen, te Pas, Kanai, van der Smagt, & Verstraten,
2004). Similarly, contextual factors can modulate the pattern of spontaneous disappearance during MIB (Bonneh, Cooperman, & Sagi,
2001; Graf et al.,
2002). All these phenomena are thus likely to be part of a more general phenomenon of spontaneous perceptual reorganization that is not restricted to the subjective elimination of parts of the visual scene (Leopold & Logothetis,
1999).