Visual detection and perceptual independence: Assessing color and form

Abstract

Visual stimuli are multidimensional. One important perceptual problem is to determine how the dimensions are combined. One important aspect of dimensional combination is whether the dimensions are perceptually independent or perceptually correlated. Anew task is presented-the visual detection task-that directly assesses the degree of perceptual correlation between any two dimensions. Two experiments were conducted that assess the degree of perceptual correlation between form and color during the early stages of perceptual analysis. The results show that form and color are not perceptually independent. Inaddition, the pattern of perceptual correlation found indicates that form and color are not processed independently. The pattern of results constrains all models of early vision. A model of early vision based on active signal modulation is proposed.

Direct estimation of multidimensional perceptual distributions: Assessing hue and form

“…The present experiment is an extension of Cohen (1997). Cohen reported a visual detectionexperiment that provided evidence that color and form are not detected independently in early vision.…”

“…Each analysis was first calculated on the individual participant's data and then concatenatedacross participantsusing a summedz meta-analysis (for a detailed description of the analysis, see Cohen, 1997;Rosenthal & Rubin, 1986;Strube, 1985;Strube & Miller, 1986). The summed-z meta-analysis was appropriate because the degrees of freedom associated with each t test were large enough for the t distribution to be a good approximation of a Gaussian.…”

“…However, the spatial position of boundaries around visual objects in different feature dimensions tends to be correlated. To avoid losing this potentially valuable source of information, the human visual system may have evolved a mechanism that facilitates the sharing of boundary position information between processing streams (see Cohen, 1997;Kubovy, Cohen, & Hollier, 1999). Such a system would have the economic advantages of modularity and the accuracy advantages of a unitary system.…”

The use of multiple cues in mate choice

“…Multimodal signals enhance signal performance through intersensory facilitation, while unimodal multicomponent signals mainly improve the specificity of the information received along a single sensory channel, although the components can interact in a similar manner to those in bimodal compounds (Cohen, 1997;Aydin & Pearce, 1997).…”

An ecological approach to cognitive (im)penetrability

“…In a series of seven experiments studying preattentive vision we (Cohen 1997;Kubovy et al, in press) have collected considerable evidence in favor of our theory. In these studies we have shown that (1) when different feature dimensions form coincident boundaries, these boundaries are detected better than would be expected if the modules were independent; (2) when different feature dimensions form inconsistent boundaries, these boundaries are detected more poorly than would be expected if the modules were independent.…”