Intermediate-level Visual Processing And The Perception Of Inside/outside Spatial Relations
R. D. B. Wright · Scholarship@Western (Western University) · 1989
The visual perception of inside/outside spatial relations often appears to be immediate and effortless. However, it is becoming increasingly apparent that the processes underlying this perception are numerous and complex. According to Ullmann, these processes can be characterized as sequences of basic operations called visual routines. Each routine consists of different combinations of operations which allow the visual system to establish object shapes and to extract spatial relations between objects. The research described in this thesis involved manipulations of display parameters for tasks in which observers made judgements about whether a target was inside or outside of a bounding figure. It was found that variations of stimulus size, location, and relative temporal onsets of stimuli reliably and systematically affected inside/outside response times. Therefore, the nature of the basic operations involved in this perception can be investigated by examining the factors that affect it. In particular, the results suggest that operations like region colouring, contour tracing, and shifts of processing focus may have been invoked to determine the relation. This is consistent with Ullman's claim that the perception of spatial relations is mediated by a number of subprocesses operating together as a visual routine.