Semantic Congruity Effects and Theories of the Comparison Process

Two experiments requiring comparisons of point locations on the line demonstrate that the magnitude of the response-time-based congruity effect parallels the form of the macro and the micro speed-accuracy trade-off function. This is predicted from the evidence accrual class of theories but is contrary to either the propositionally based semantic coding theory or the expectancy view. Very large accuracy-based congruity effects with comparisons of point locations in the plane are evident. Congruity effects arise because the duration of each evidence accrual is increased and the quality of the information is reduced as the distance of the stimulus representations from the instruction-activated reference point increases. This evidence accrual view is extended to account for the properties of perceptual and symbolic comparisons.