Letter position coding across modalities: the case of Braille readers.
BACKGROUND
The question of how the brain encodes letter position in written words has attracted increasing attention in recent years. A number of models have recently been proposed to accommodate the fact that transposed-letter stimuli like jugde or caniso are perceptually very close to their base words.


METHODS
Here we examined how letter position coding is attained in the tactile modality via Braille reading. The idea is that Braille word recognition may provide more serial processing than the visual modality, and this may produce differences in the input coding schemes employed to encode letters in written words. To that end, we conducted a lexical decision experiment with adult Braille readers in which the pseudowords were created by transposing/replacing two letters.


RESULTS
We found a word-frequency effect for words. In addition, unlike parallel experiments in the visual modality, we failed to find any clear signs of transposed-letter confusability effects. This dissociation highlights the differences between modalities.


CONCLUSIONS
The present data argue against models of letter position coding that assume that transposed-letter effects (in the visual modality) occur at a relatively late, abstract locus.
ERI-Lectura and Departamento de Metodología, Universitat de València, Valencia, Spain. mperea@valencia.edu
Manuel
M
Perea
Cristina
C
García-Chamorro
Miguel
M
Martín-Suesta
Pablo
P
Gómez
D003657:Decision Making; D006801:Humans; D011932:Reading; D021641:Recognition, Psychology; D012660:Semantics; D012682:Sensory Aids; D014110:Touch