Language Shift Effect on Memory Generalization of Chinese-English Bilinguals

Language shift occurs when people learn information in one language but recall it in another language. This mismatch between encoding and retrieval language is found to impair memory accuracy when memory is tested immediately after learning. However, does the observed language shift effect still exist after a certain period of delay? Would it influence other aspects of memory, especially memory generalization? To address these two questions, we performed a memory experiment among unbalanced Chinese-English bilinguals. In the experiment, participants were required to read two stories (one in English, one in Chinese) and to retell the stories in Chinese from their memories afterward. Delay interval was manipulated in the experiment where participants either took memory recall tests immediately after story-reading or after 24 hours' delay. To analyze memory generalization, we coded the generalized words participants used to retell the stories. The results suggest that language shift (encoding in English and retrieving in Chinese) leads to a more generalized description in a memory recall task. However, the observed language shift effect disappears after 24 hours' delay. It can be concluded that language shift impacts bilingual learners' memory generalization in immediate recall tests, but such effect disappears after 24 hours' delay, which indicates the key role of delay interval in modulating language shift effect.