Integration of stereo and texture cues in the formation of discontinuities during three-dimensional surface interpolation

A series of stereograms are presented which demonstrate that texture boundaries can strongly influence the perception of discontinuities between neighbouring three-dimensional (3-D) surfaces portrayed by means of stereo cues. In these demonstration figures, no stereo information is available in the immediate vicinity of the boundary between the two 3-D stereo surfaces because all texture in that region is removed in one eye's view. On the other hand, various forms of texture boundary information are provided in the resulting monocular region. This stimulus paradigm is used to explore the question: what influence does texture boundary information have on the nature of the perceived 3-D surface that is interpolated between two stimulus regions which carry stereo cues? It is shown that if a clear-cut texture boundary is present in the monocular region then this is used by the human visual system to fix the perceived location of 3-D crease and step surface discontinuities between the stereo regions. Collett (1985) explored this issue with a similar methodology and reported weak and unreliable assistance from monocular texture boundaries in helping shape 3-D stereo surface discontinuities. The strong and robust phenomena demonstrated here seem to rely on two main differences between the present stimuli and those of Collett. In the present stimuli, figurally continuous textures containing strong texture boundaries are used, together with a technique for minimising the complications, including binocular rivalry, that arise from the borders of the stimulus regions present in only one half of each stereogram.     

". . . On the Basis of Velocity Clues Alone": Some Perceptual Themes 1946-1996

Three factors that have transformed perceptual research in the last fifty years are the digital computer, single-unit electrophysiology, and molecular biology. Amongst the developments in which members of the Experimental Psychology Society have been central are: the recognition of the role of optic flow in spatial vision; the demonstration that our perceptual systems contain parallel pathways extracting different information from the sensory array; the identification of specific detectors that can be selectively adapted in psychophysical experiments; and the transfer of the concepts of fourier analysis from audition to vision. The history of Opponent Process Theory offers an example where experimental psychologists have been misled by too simple an interpretation of physiological recordings.     

Attitudes and Attraction: Optimism and Weight as Explanations for the Similarity–Dissimilarity Asymmetry

The positive link between attitude similarity and attraction is one of the fundamental outcomes in social psychology. However, attitude dissimilarity seems to be a stronger driver of this relationship than attitude similarity. The authors review the evidence on this similarity–dissimilarity asymmetry, and discuss two explanations. One is that people generally enter into interactions with optimism, and so supposedly neutral partners are often seen as mildly positive. Another is that dissimilar attitudes carry greater weight than similar attitudes in cognitive processes. Implications of these mechanisms for wider issues in person perception and attitude structure are discussed, connecting them with more recent theories of attitudinal ambivalence and evaluative space.