Naming and categorization of tilted alphanumeric characters do not require mental rotation

Abstract

Single letters and numbers were shown at different angular orientations in the frontal plane, in both forward and backward (mirror-image) versions. In three separate conditions, subjects were required to discriminate the stimuli on the basis of version, category (letter, number, and name (G, 2, etc.). There was a pronounced effect of orientation on version judgments but none at all on category and name judgments, indicating that the identification of a tilted character requires neither the assignment of a cognitive up-down axis nor mental rotation to the upright. Nevertheless, reaction times for backward versions were slower than reaction times for forward versions in both category and name conditions, implicating some sort of interhemispheric transfer process. No support was obtained for the so-called “conceptual category” effect in that reaction times for category judgments were consistently slower than reaction times for name judgments. © 1980, The Psychonomic Society, Inc.. All rights reserved.