Bottom-up and top-down infulences on the processing of Kana and Kanji

Syoichi Iwasaki, Ph.D
Cognitive Psychology Laboratory, Tohoku University, Sendai, Japan 　

Abstract:
Several lines of evidence have suggested that perceptual processing involves both bottom-up and top-down processes.  For example, in attentional capture it was once believed that abrupt onset unconditionally captures attention.  However, more recent studies have pointed to the importance of attentional set for obtaining attentional capture.  In this study, we used two experimental paradigms to demonstrate involvement of both bottom-up and top-down processes even for the processing of task-irrelevant stimulus dimensions.  In one type of experiments, Kanji and pseudo-Kanji were used as background items for identifying targets in a rapid serial visual presentation (RSVP).  Since two targets in the RSVP stream were alphabet letters, it sufficed for the participants only to process the background Kanji and Kanji-like patters just to be able to discriminate them from targets.  However, identification of the letters was harder when they were embedded in the stream of pseudo-Kanji characters than of Kanji characters.  This finding suggests that processing of Kanji involved both bottom-up and top-down processes with access to lexicon helping ongoing processing being performed in shorter delay.  In the second series of experiments, Stroop-like stimuli were used to explore the possible bi-directional interactions of bottom-up and top-down processes in the processing of Kana and Kanji.  Participants were asked to name the colors of two to four letter words and non-words, which were written in either Kana or Kanji.  Compared to non-readable stimuli, color-naming was slower to stimuli composed of Kana.  In contrast, color-naming latencies of Kanji stimuli were comparable to those of non-readable stimuli.  This finding suggests that over-learned and easy-to-pronounce patterns like Kana induces even in a non-task relevant situation automatic reading tendency or automatic demand on attentional resources, resulting in slower responses.