An investigation of perceptual and decisional influences on the perception of hierarchical forms

When observers are asked to identify the global and local dimensions of hierarchical forms, their responses are typically faster when the dimensions are consistent rather than inconsistent. This effect, which we refer to as the dimensional consistency effect, has been demonstrated numerous times in paradigms requiring responses to a single dimension. However, most hypotheses regarding dimensional consistency effects address the simultaneous perception of both dimensions, and the manner in which the information about these dimensions may (or may not) 'interact'. Most explanations of the dimensional consistency effect attribute the effect to perceptual influences. The present study uses the constructs of general recognition theory (Ashby and Townsend, 1986 Psychological Review 93 154-179) to represent the source of the effect in terms of both perceptual and decisional influences. In addition, a complete identification response paradigm was used to collect data on the simultaneous perception of both global and local dimensions of hierarchical forms. Analyses of multidimensional signal detection measures and fits of parametric models of the perceptual space were used to guide inferences, with all sources of evidence pointing to both perceptual and decisional influences.