摘要：Cognitive processes that recognize written words must consider not only letter identity but also letter position. Various schemes for representing letter position in reading have been proposed, including schemes based on a letters distance from the beginning or midpoint of the word, its role in an orthographic syllable, and its context of surrounding letters. For example, the A in CARPET might be represented as the second letter from the beginning of the word (position B+2), the nucleus of the first orthographic syllable (Nai), the letter appearing between C and R (position C_R), or so forth.
