|Budget Amount *help
¥3,300,000 (Direct Cost : ¥3,300,000)
Fiscal Year 1998 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1997 : ¥2,200,000 (Direct Cost : ¥2,200,000)
Numbers are difficult to process when people are using a second language (L2), i.e., their non-native language, even after they have lived in the L2 environment for a long time, or even if they are perfect bilinguals. Three series of cognitive psychological experiments have been conducted in order i) to investigate the phenomena in experimental paradigms, ii) to identify conditions for the phenomena, and iii) to demonstrate the validity of our hypothesis about the cause of the phenomena ; namely, the dependency of number processing upon native languages. The first series of experiments with naming and reading-aloud tasks showed that Japanese native speakers needed a longer time to respond to numbers in English (their L2) only when they had to process individual number as meaningful entities. The second series of experiments employed quasi-Stroop tasks, in which subjects were to name a series of pictures and numbers as fast as possible in English or in Japanese. Analysis of errors demonstrated that numbers caused many more replacement errors ; i.e., responding in L1 instead of L2. These results support the hypothesis that number processing depends on the native language. The third series of experiments were designed to exclude the factor of language in the response, and used tasks in which stimuli were presented auditorily and subjects responded by pushing a Yes/No button. Both auditory - visual matching tasks and continuous decision tasks (to decide whether the stimulus is bigger or former in a series compared with the previously presented one) showed that numbers were more difficult and slower to process in English, even though they were much easier compared to nouns and characters. The specificity of number phenomena in human cognitive systems was discussed based on these experimental results, and modeling of this phenomena are now under way.