Numerical judgments with Kanji and Kana.

Native Japanese speakers were timed to judge the numerically larger of two numbers, written either in Kanji (an ideographic script) or in Kana (a syllabic script). For Kanji, irrelevant variations in the physical size of the numbers speeded reaction time in one condition and slowed it in another. Such variations only slowed processing for Kana, except when subjects had previously performed with Kanji. For both scripts, reaction time varied with the numerical difference between the two numbers but not in an identical manner. The implications of the findings are considered.