Abstract: In previous studies, we proposed hypothesis that stroke distance accounted for the influences of various Chinese character forms on visual perception of Chinese characters. Stroke distance was measured in horizontal and vertical dimensions and represented with the two quantities: horizontal and vertical distance. In fact, the two quantities might be integrated in some way. A new algorithm aiming to integrate horizontal and vertical distance was proposed in this present paper. When a character was presented on a monitor controlled by a computer, the stroke distance was measured in pixel. The new algorithm could be represented with the following formula: D=(∑d i )/n,in which n referred to the number of two pixels that could be directly connected with a line in horizontal or vertical dimension and d referred to the distance between the two pixels. The new algorithm was advisable for analyzing characters used in previous experiments. It was also applied to analyze all the paired horizontally and vertically structured characters that were selected from the Basic Chinese Character Set (6724 characters). The results showed that, generally, the horizontally structured characters had larger stroke distance than the vertically structured characters regardless of the number of radical. Structure effect refers that people responded to the horizontally structured characters with less time and greater accuracy than the vertically structured characters. In previous studies, we presented the explanation based on stroke distance. The Present study further tested the hypothesis. Two experiments were conducted. In experiment 1, a group of paired horizontally and vertically structured characters with statistically equal stroke distance were selected by applying the new algorithm. Participants in a dimmed room were asked to identify the characters presented on the computer monitor as quickly and accurately as possible. The results showed that the influence of Chinese character structure on visual identification disappeared. In experiment 2, the algorithm was applied to a selected group of paired characters in which the distance of vertically structured characters was larger than that of horizontally structured characters. Under this condition, we found that the structure effect was reversed. Vertically structured characters were easier to identify than horizontally structured characters. The results obtained from these two experiments were compatible with the hypothesis that stroke distance contributed to the structure effect. Meanwhile, the new algorithm for measuring stroke distance of Chinese characters was found to be helpful.

Key words: stroke distance, algorithm for stroke distance, structure effect