Abstract
We studied the relationship between texture orientation and shape medial axes in the discrimination of texture-defined shapes. Orientation-based texture segmentation is well-studied, but has rarely been investigated using texture patches with complex shape. We found that alignment between texture orientation and the skeletal axis of a figural region improved the segmentation strength of the figure from a randomly oriented background. When texture was aligned with the figure axis, shape discriminations were made at lower threshold texture coherence levels than when the offset between texture orientation and figure axis was 45 degrees. Performance recovered as the offset was increased further to the maximum of 90 degrees. The alignment effect is attributable to the orientation of the skeletal axis itself, not the orientation of the figure edges; these two factors were deconfounded in our “peanut”-like shapes where contours undulated relative to the main axis orientation. A second study using multi-part shapes showed a similar pattern of results: performance was best when the texture was locally aligned with the skeletal axis of the enclosing part, superior even to the classically optimal case of uniform texture orientation. We conclude that the influence of shape and axial structure extends to early processes by which texture elements are aggregated to form the object itself. We discuss the implications of this conclusion for theories both of texture aggregation and of shape representation.