An analysis of hierarchical processing in visual perception.

Abstract

Perception is viewed as a process in which attributes of a stimulus are analyzed in step-wise fashion. Two experiments were carried out in which the attributes of spatial location and identity were examined for two types of materials. The results indicate that identification of letters requires more stimulus energy than identification of lines. In turn, there were no differences between identification of lines, localization of lines or localization of letters. In general, these results support a hierarchical processing hypothesis.RECENTLY, SEVERAL INVESTIGATORS have suggested that perceptual processing may be composed of a series of hierarchical tests or analyses performed on a sensory input (Egeth, 1967;Posner & Mitchell, 1967). This suggestion is not particularly new since it has been known for a long time that brightness and form recognition thresholds differ considerably (Forgus, 1966), apparently because analysis of form occurs corticaUy (e.g., Lashley & Franks, 1934), while certain aspects of brightness are processed at a lower level. What is interesting, however, is the suggestion that within form recognition it is possible to make a much finer distinction in terms of the physiological level at which different types of information are analyzed. Some support for such a position has been provided physiologically by Hubel and Wiesel (1959;Hubel, 1963). These investigators have shown that a variety of different neurons exist in the striate cortex of the cat; each of these neurons responds to a specialized type of stimulation. "Simple" cells respond only to lines or bars of particular orientations with each cell responding to its own special orientation and physical location. For example, a cell with vertically oriented field will respond strongly only if die stimulus is oriented vertically in a particular area of the retina; when the stimulus is oriented in any other direction 1 The early stages of this research and the computer analyses of the data were supported in part by Defence Research Board of Canada, Grant No. 9401-26 to Dr. M. P. Bryden of the University of Waterloo. The other aspects of these experiments were supported by National Science Foundation Grant No. GB-7848. The authors would like to thank R. H. Jackson for assistance in testing the Ss in Experiment n and Dr. D. J. K. Mewhort for computer analysis of the data and for comments.2

The face-detection effect: Configuration enhances detection

“…By itself, this is not surprising. It is known that observers can localize a complex target without being able to identify it (Breitmeyer, 1974;Dick & Dick, 1969;Smythe & Finkel, 1974). What is counterintuitive about our results is that the processes underlying detection are influenced by the information contained in the arrangement of the pattern's individual components.…”

“…(3) By using detection threshold as the dependent variable, subjects should, at threshold, be equally unaware of the stimulus, whether it be an upright or an inverted face. This belief is based on work that shows that target localization under backward masking happens at shorter SOA values than does target identification (Breitmeyer, 1984, p. 133;Dick & Dick, 1969;Smythe & Finkel, 1974).…”

“…It is known that detection precedes identification or classification for many stimuli (Breitmeyer, 1984;Dick & Dick, 1969;Smythe & Finkel, 1974). This experiment was designed to compare the detection threshold to the classification threshold.…”

“…representation, and detection of a stimulus precedes the analysis of a visual scene (Dick & Dick, 1969;Smythe & Finkel, 1974). Unlike identification, any perceived change in the visual field is all that is necessary to produce the detection of a stimulus (Dember & Warm, 1979).…”

The object-detection effect: Configuration enhances perception

“…133;Dick & Dick, 1969;Smythe & Finkel, 1974). Faces and three-dimensional objects might both be thought of as familiar in the sense that both are exemplars of a higher order category.…”