Can letter position encoding be modified by visual perceptual elements?

A plethora of studies has revealed that letter position coding is relatively flexible during word recognition (e.g., the transposed-letter [TL] pseudoword CHOLOCATE is frequently misread as CHOCOLATE). A plausible explanation of this phenomenon is that letter identity and location are not perfectly bound as a consequence of the limitations of the visual system. Thus, a complete characterization of letter position coding requires an examination of how letter position coding can be modulated by visual perceptual elements. Here we conducted three lexical decision experiments with TL and replacement-letter pseudowords that manipulated the visual characteristics of the stimuli. In Experiment 1, each syllable was presented either in a different colour or monochromatically (e.g., [Formula: see text] vs. [Formula: see text]) with the transposition occurring across syllables. In Experiment 2, the critical letters had a consistent contrast or not (e.g., [Formula: see text] vs. [Formula: see text]). In Experiment 3, the stimuli were presented either simultaneously or serially, letter by letter (i.e., as occurs in braille reading). Results showed that whereas colouring differently each syllable only produced a small nonsignificant reduction of the TL effect, the other two manipulations—presenting the two critical letters with an altered contrast and presenting the letters one at a time—reduced, but did not eliminate, the magnitude of the TL effect relative to the regular format. Although these findings are consistent with models that postulate an early perceptual locus of the TL effect, the robustness of the TL effect suggests that letter position coding also has an orthographic abstract component.