On coding the position of letters in words: a test of two models

Open-bigram and spatial-coding schemes provide different accounts of how letter position is encoded by the brain during visual word recognition. Open-bigram coding involves an explicit representation of order based on letter pairs, while spatial coding involves a comparison function operating over representations of individual letters. We identify a set of priming conditions (subset primes and reversed interior primes) for which the two types of coding schemes give opposing predictions, hence providing the opportunity for strong scientific inference. Experimental results are consistent with the open-bigram account, and inconsistent with the spatial-coding scheme.