Visual texture segregation based on orientation and hue

Abstract

We investigated visual texture segregation, using a task for which reaction time to locate a discrepant quadrant in an array of 36 elements was the dependent measure. Two dimensions of segregation were used: line orientation (horizontal vs. vertical, horizontal vs. left diagonal, and left vs. right diagonal) and hue (9 vs. 7 Munsell color steps). Levels on these two dimensions were varied singly to produce control arrays, in orthogonal combination to measure possible interference effects, and in redundant combination to measure possible facilitation effects. Segregation for control arrays was much more difficult when the two diagonal lines produced regions of texture than when arrays used lines involving one or two main axes, and 7-step hue-difference arrays were more difficult to segregate than 9-step arrays, as expected. Orientation and hue were equally effective in producing fast texture segregation when used with optimal levels. The pattern of interference and facilitation for orthogonal and redundant combinations depended on the particular pair of line orientations used to produce texture: With horizontal and vertical lines, there was symmetric interference of each dimension on the other, as well as a redundancy gain. With horizontal and left diagonal lines, there was asymmetric interference of hue variation on orientation segregation, and no redundancy gain. With the two diagonals, there were symmetric interference and strong redundancy gains. These results clarify why different line orientations provide different effectiveness in texture segregation, and suggest that both interstimulus confusability (as with the two diagonals) and intrastimulus stability (as with horizontal and vertical lines) properties determine the ability of a dimension to interfere with, or to be interfered with by, another dimension in texture segregation.

Interference and dominance in texture segregation: Hue, geometric form, and line orientation

“…The primary aim of the present experiments was to provide further support for the proposal that within-region similarity is an important factor in texture segregation (Beck, 1982;Callaghan et al, 1986;Enos, 1986;Olson & Attneave, 1970). The procedure established by the author was employed in the present experiments with stimuli that varied on the dimensions of hue and geometric form.…”

“…On the basis of the Gestalt notion of similarity grouping, it has been proposed that the process of texture segregation will be enhanced not only by high dissimilarity of elements between regions, but also by high similarity of elements within regions (Beck, 1982;Callaghan et al, 1986;Eons, 1986;Olson & Attneave, 1970). Although much research has been devoted to the study of between-region differences, at least two lines of evidence support the importance of withinregion differences.…”

“…Studies of texture segregation have focused on the determination of the basic properties of the stimulus that mediate segregation (i.e., visual primitives), as well as on the illumination of the nature of the segregative process itself. From the former studies, and from studies using a visual-search pop-out paradigm, we have learned that texture segregation and popout are easily produced by the properties of line orientation (Beck, 1966(Beck, , 1967(Beck, , 1972Callaghan et al, 1986;Olson & Attneave, 1970;Treisman & Gormican, 1988), hue Treisman, 1982;Treisman & Gelade, 1980;Treisman & Gormican, 1988), brightness Treisman & Gormican, 1988), or form (Treisman, 1982;Treisman & Gelade, 1980;Treisman & Gormican, 1988). There is indication that the presence versus absence of line terminators (Julesz, 1975(Julesz, , 1981Treisman & Souther, 1985), line length (Beck, 1974;Treisman & Gormican, 1988), and curvature (Treisman & Gormican, 1988), as well as the property of closure (Treisman & Paterson, 1984) also promote strong segregation.…”

“…It is clear that the main objectives of the revised feature-integration theory are to establish the primitive features of visual perception (see next section for details), to describe how these features are initially coded by the visual system (independent feature maps linked to a master location map), and to determine how the initial independent registration of features is related to the conscious experience of object perception (narrowing of the focus of attention to a discrete spatial Copyright 1989 Psychonomic Society, Inc. location). With the elimination of the dichotomy view of attention, many of the previously discrepant findings from texture-segregation research (e.g., Beck, 1982;Callaghan, Lasaga, & Garner, 1986) may now fit nicely in the revised feature-integration view of perception.…”

“…In one line of investigation Callaghan et al, 1986), it has been shown that if the similarity of elements within a region is reduced by randomly varying the level of an irrelevant dimension across all elements in the array, then performance is poor relative to a control array having identical elements within a region. In a second line of research, Eons (1986) has reported that ease of segregation is determined by the context in which a target region is embedded.…”