The use of structural diagnostics in recognition.

Abstract

The suggestion of Krueger (1973) and others that wholistic processes underlie certain perceptual judgments is taken up in this paper. It is argued that properties such as bilateral symmetry can have a "diagnostic" significance for visual matching tasks. Diagnosticity means that if the property is present the appropriate response to a stimulus could theoretically 'be determined without any other analysis of the stimulus. Experiments 1 and 2 indicate that symmetry is exploited as a diagnostic property for the simultaneous same-different judgment. Displays that show the diagnostic form produce short reaction times. These experiments also show that the diagnosticity effect can be demonstrated independent of potentially confounding factors such as simplicity or redundancy. Experiments 3, 4, and 5 discount further confounding factors and also show that other properties, notably parallelism and colinearity of stimulus elements, can also be exploited as diagnostics in the simultaneous matching task. Diagnostics can have a structural or relational form. Diagnostic features are viewed as two-place structural predicates. Whether these diagnostics always have the same underlying form or not, the need for some representation of structure is a prerequisite for understanding even these simple recognition phenomena.When pairs of letters of the alphabet are simultaneously presented to an observer the time taken to judge the items the same is often less than the time taken to judge them different (see Nickerson, 1972, for a review). This finding has led a number of authors (e.g., Bamber, 1969;Krueger, 1973) to suggest that a wholistic analysis of the stimuli underlies the same judgment whereas an analytic process underlies the different judgment. The reasoning behind the two-process theory of character comparison is that if an analytic process were always used (in which stimulus elements were separately selected and compared) one would expect same judgments to be slower

Symmetry and similarity effects in the comparison of visual patterns

“…This is supportive of symmetry as a "diagnostic" allowing fast "same" responses (Fox, 1975),since a diagnostic would be expected to become more beneficial as similarity increased. In effect, the presence of similar "different" pairs should make subjects cautious and thus slow in making same responses; symmetry can then exert a larger diagnostic effect than otherwise.…”

“…If the disparity varies with visual similarity (Bindra et al, 1968), this would suggest either a two-process letter-comparison model or a single-process model combined with a criterion shift. Third, the use of symmetry as a "structural diagnostic" is investigated, since it has been found that symmetry can speed "same" responses (Fox, 1975;Richards, 1978), an observation unaccounted for in any of the preceding models. If found, such an effect would implicate a two-process comparison model, since symmetry should not in itself affect a difference count.…”

Selective attention to global and local levels in the comparison of hierarchical patterns

“…As a result, the comparison process could be affected by two factors. One factor is symmetry of the whole display (Fox, 1975). If global symmetry is salient in some way, it could facilitate "same"/"different" judgments on the global dimension (see also Navon, 1983).…”

Visual signalling by asymmetry: a review of perceptual processes

“…In humans, it has been claimed that symmetry about a vertical axis is more salient than symmetry about any other axis (Mach 1959;Rock & Leaman 1963;Goldmeier 1972;Rock 1973;Corballis & Roldan 1975;Fox 1975;Barlow & Reeves 1979;Fisher & Fracasso 1987). Explicitly, there are data to indicate a hierarchy in ease of detection so that symmetry in a vertical plane is easiest to detect, followed by horizontal symmetry and then diagonal symmetry (Palmer & Hemenway 1978;Barlow & Reeves 1979;Royer 1981).…”