Objective ages of acquisition for 3300+ simplified Chinese characters.

We report the construction of two age-of-acquisition (AoA) norms for 3300+ characters in simplified Chinese, which make up about 99% of the texts used in daily life. We determined a character's AoA according to the time in which the character is formally learned in two sets of leading textbooks of Chinese in compulsory education, published respectively on the basis of the 2001 and 2011 national curriculum. Apart from having a significantly larger coverage of characters than previous norms, the current norms also outperformed them in explaining accuracy and reaction times in four large-scale databases for character decision, character naming, or character handwriting, even after controlling for the effects of frequency, number of meanings, and number of strokes. The explanatory advantage of the current norms suggests that, compared to earlier norms, the current norms capture more up-to-date character AoAs; these findings also highlight the diachronic nature of some lexical variables such as AoA and frequency. The developed objective AoA norms can be used for subsequent research on Chinese character recognition or production.