Previous empirical studies have shown that information along visual contours is known to be concentrated in regions of high magnitude of curvature, and, for closed contours, segments of negative curvature (i.e., concave segments) carry greater perceptual relevance than corresponding regions of positive curvature (i.e., convex segments). Lately,…

A fundamental issue in the design and the interpretation of experimental studies of perception relates to the question of whether the participants in these experiments could perform the perceptual task assigned to them using another feature, or cue, than that intended by the experimenter. An approach frequently used by auditory- and…

A growing number of studies claim that spatial attention can be split "on demand" into several, segregated foci of enhanced processing. Intrigued by the theoretical ramifications of this proposal, we analyzed 19 relevant sets of experiments using four methodological criteria. We typically found several methodological limitations in each study that…

Perceiving objects activates the representation of their affordances. For example, experiments on compatibility effects showed that categorizing objects by producing certain handgrips (power or precision) is faster if the requested responses are compatible with the affordance elicited by the size of objects (e.g., small or large). The article…

Although in traditional attention research the focus of visual spatial attention has been considered as indivisible, many studies in the last 15 years have claimed the contrary. These studies suggest that humans can direct their attention simultaneously to multiple noncontiguous regions of the visual field upon mere instruction. The notion that…

A wealth of empirical evidence has now accumulated concerning animals' categorizing photographs of real-world objects. Although these complex stimuli have the advantage of fostering rapid category learning, they are difficult to manipulate experimentally and to represent in formal models of behavior. We present a solution to the representation…

M. Singh and B. L. Anderson proposed a perceptual theory of achromatic transparency in which the perceived transmittance of a perceived transparent filter is determined by the ratio of the Michelson contrast seen in the region of transparency to that of the background seen directly. Subsequently, B. L. Anderson, M. Singh, and J. Meng proposed that…

All of the data reported in Robilotto, Khang, and Zaidi (2002) Robilotto and Zaidi (2004), and Singh and Anderson (2002) are consistent with Robilotto and Zaidi's theory that perceived transparency (or opacity) is determined by the perceived contrast of the filter region. Kasrai and Kingdom's (2001) results also appear largely consistent with the…

Visual backward masking is a versatile tool for understanding principles and limitations of visual information processing in the human brain. However, the mechanisms underlying masking are still poorly understood. In the current contribution, the authors show that a structurally simple mathematical model can explain many spatial and temporal…

Comments on an article by Bressan. Recently, a double-anchoring theory (DAT) of lightness perception was proposed (P. Bressan, 2006), which offers explanations for all the data explained by the original anchoring theory (A. Gilchrist et al., 1999), as well as a number of additional lightness phenomena. Consequently, DAT can account for an…

The relationship between luminance (i.e., the photometric intensity of light) and its perception (i.e., sensations of lightness or brightness) has long been a puzzle. In addition to the mystery of why these perceptual qualities do not scale with luminance in any simple way, "illusions" such as simultaneous brightness contrast, Mach bands,…

The specific gray shades in a visual scene can be derived from relative luminance values only when an anchoring rule is followed. The double-anchoring theory I propose in this article, as a development of the anchoring theory of Gilchrist et al. (1999), assumes that any given region (a) belongs to one or more frameworks, created by Gestalt…

Are words read visually (by means of a direct mapping from orthography to semantics) or phonologically (by mapping from orthography to phonology to semantics)? The authors addressed this long-standing debate by examining how a large-scale computational model based on connectionist principles would solve the problem and comparing the model's…

A new theory linking information extraction patterns to the visual perception of direction and extent is presented. Seven demonstration experiments employ predictions from efferent considerations to create a new set of illusions of direction and extent and to demonstrate new predictable variations in the magnitude of some classical illusion…

An alternative way of attempting to understand visual hemispheric specialization is presented. A theory of certain high-level processing subsystems is formulated in light of an analysis of problems that must be solved by the visual system and the constraints on the solutions to these problems. (Author/LMO)