Chapter 5 - Getting the Information: Visual Space and Time

Abstract

This chapter discusses the perceptual and cognitive structure of space, taking into account both how depth is perceived and the costs of navigation to access information. It also discusses the ways in which depth is perceived. The cognitive organism acts on visual information that is imaged on the retina. The perceptual egocentric space is commonly thought of in terms of the “up” dimension, the “sideways” dimension, and the “towards-away” dimension. Depth cues can be divided into those that are pictorial and those that are nonpictorial. Perceptual space is also flattened in terms of its information content, with much less information being rapidly available in the towards-away (depth) direction than the sideways and up-down directions because we cannot see through most objects. The pattern-processing mechanisms of the brain operate on the two-dimensional retinal image, which means that two-dimensional image plane information is analyzed much more efficiently than depth information. The set of design principles that takes the space-time structure of perception into account is called 2.5-dimension design. The fact that the brain is capable of interpreting depth cues in a piecemeal fashion frees the designer to break the rules of perspective and make use of depth cues in different combinations, as they seem most suitable to serve the purposes of a design. The designer of interactive computer-based applications has options relating to the cost of information access.