Top-down number reading: Language affects the visual identification of digit strings

Abstract

Reading numbers aloud involves visual processes that analyze the digit string and verbal processes that produce the number words. Cognitive models of number reading assume that information flows from the visual input to the verbal production processes – a feed-forward processing mode in which the verbal production depends on the visual input but not vice versa. Here, I show that information flows also in the opposite direction, from verbal production to the visual input stage. Participants read aloud briefly-presented multi-digit strings in Hebrew, in which the order of words is congruent with the order of digits (21 = twenty-and-one), and in Arabic, in which the ones word precedes the tens word (one-and-twenty). The error-by-digit-position curve, which reflects the order in which the visual analyzer scans the digits, was affected by language: relative to Hebrew, in Arabic the error rate was slightly higher for the decade digit, indicating later processing, and slightly lower for the unit digit, indicating earlier processing. I conclude that the visual analyzer of Arabic speakers processed the unit digit before the decade digit, in accord with the language-specific order of words. The same effect was observed even within participant, when bilingual participants read numbers in Hebrew and in Arabic. I conclude that the digit scanning order is not fixed for each person, but is determined in real time, according to the current linguistic context, via a top-down, verbal-to-visual information flow.