Illusory size determines the perception of ambiguous apparent motion

The visual system constructs perceptions based on ambiguous information. For motion perception, the correspondence problem arises, i.e., the question of which object went where. We asked at which level of processing correspondence is solved – lower levels based on information that is directly available in the retinal input or higher levels based on information that has been abstracted beyond the input directly available at the retina? We used a Ponzo-like illusion to manipulate the perceived size and separations of elements in an ambiguous apparent motion display. Specifically, we presented Ternus displays – for which the type of motion that is perceived depends on how correspondence is resolved – at apparently different distances from the viewer using pictorial depth cues. We found that the perception of motion depended on the apparent depth of the displays, indicating that correspondence processes utilize information that is produced at higher-level processes.

Pictorial Depth Cues in Young Children’s Drawings of Layouts and Objects

Humans have been faced with the challenges of pictorial production since at least the Paleolithic. Curiously, while the capacity to navigate layouts and recognize objects in everyday life comes almost effortlessly, inherited from our evolutionary past, the capacity to draw layouts and objects is more effortful, often needing time to improve over the course of an individual’s development and with the technological innovations acquired through culture. The present study examines whether young children might nevertheless rely on phylogenetically ancient spatial capacities for navigation and object recognition when creating uniquely human pictorial art. We apply a novel digital coding technique to a publicly available dataset of young children’s drawings of layouts and objects to explore children’s use of classic pictorial depth cues including size, position, and overlap. To convey pictorial depth, children appear to adopt several cues, without a preference among them, younger than had been suggested by previous studies that used other, less rich, analytic techniques. Moreover, children use more cues to pictorial depth in drawings of layouts versus objects. Children’s creation of uniquely human pictorial symbols may thus reflect their heightened use of depth for navigating layouts compared to recognizing objects, both cognitive capacities that humans share with other animals.

Architectural Perspective in Italian paintings of the 14th century

This paper discusses the system of the pictorial depth representation, typical for Giotto and other Italian artists of 14th century. Differing from the linear perspective, this system has a number of peculiar features, and its own consistent logic for the formation of pictorial space. The paper is especially focused on the contradictions of such a system, which lead to the appearance of impossible figures, and the ways in which the artists solved these difficulties.

Double Vision as a Pictorial Depth Cue

‘Double images’ are a little-noticed feature of human binocular vision caused by non-convergence of the eyes outside of the point of fixation. Double vision, or psychological diplopia, is closely linked to the perception of depth in natural vision as its perceived properties vary depending on proximity of the stimulus to the viewer. Very little attention, however, has been paid to double images in art or in scientific studies of pictorial depth. Double images have rarely been depicted and do not appear among the list of commonly cited monocular depth cues. In this study we discuss some attempts by artists to capture the doubled appearance of objects in pictures, and some of the relevant scientific work on double vision. We then present the results of a study designed to test whether the inclusion of double images in two-dimensional pictures can enhance the illusion of three-dimensional space. Our results suggest that double images can significantly enhance depth perception in pictures when combined with other depth cues such as blur. We conclude that double images could be added to the list of depth cues available to those wanting to create a greater sense of depth in pictures.