Abstract
What visual cues promote grouping of local image features into global spatial form? Several previous studies suggest that synchronous stimulus changes support the grouping of spatially segregated elements, whereas asynchronous changes lead to stimulus segregation. However, these experiments often confound temporal synchrony (i.e., the precise timing of the changes) with temporal structure (i.e., the pattern or “rhythm” of the changes over time). In the current study, we investigate the extent to which spatial grouping from temporal cues can be attributed to structure versus synchrony. Observers viewed arrays of Gabor patches in which spatial frequency changed stochastically over time. The timing of the changes yielded two opposing perceptual organizations. One organization involved grouping those elements having the same point process (i.e., same temporal structure), but whose individual changes were delayed slightly relative to one another (i.e., asynchronous). The second organization involved grouping those elements that changed synchronously more often than not, but that changed according to different overall temporal patterns (i.e., different temporal structures). Perceived spatial organization proved to depend primarily on temporal structure, rather than temporal synchrony. That is, observers systematically grouped elements that changed according to the same general pattern over time, even though the changes themselves were asynchronous. Furthermore, different global patterns of change served as a consistent basis for segregation. These findings will be discussed in the context of ongoing controversies concerning the role of temporal synchrony in stimulus binding.
Funded by NEI EY07760 to RB.