dc.description.abstract | Memory research has indicated the prominent role of phonology for retaining verbal materials in short-term memory in monolinguals. However, there has been limited research addressing how non-phonological representations play roles in verbal short-term memory (VSTM), and even less is known in the context of bilingualism. The present study first aims to investigate whether the non-phonological representations give rise to the effect of first language (L1) advantage on a probed recall task. Additionally, we aim to explore the robustness of the L1 advantage effect by employing bilingual lists with mixed language modes. Moreover, we further investigate whether language-based chunking/organizing principles exist in VSTM for each language in Chinese-English bilinguals. To achieve these aims, four experiments were conducted. In the first two experiments, we manipulated the phonological complexity between pairs of approximately homophonic Chinese and English materials to examine whether the L1 advantage effect would be observed, even when the phonological information was not helpful. The results indicated that there was a significant non-phonological contribution to bilingual VSTM by demonstrating a significant L1 advantage effect in the two experiments even under articulatory suppression. In Experiments 3 and 4, we examined the robustness of the L1 advantage effect by employing bilingual lists. We also took advantage of the bilingual lists, which were composed of stimuli in two different classes (i.e., Chinese and English materials) that have been employed in the probe recalled task to reveal the organization of short-term memory, to investigate whether there are language-based chunking/organizing rules in bilingual VSTM. Inconsistent with the findings from Experiment 1 and 2, the results of Experiment 3 did not show significant difference between the recall of Chinese and English materials. We suspected that the non-significant L1 advantage resulted from the fact that participants mainly relied on phonology to retain the materials. That might be due to the increasing task difficulty by employing the bilingual lists. In Experiment 4, we employed tetrads of rhyming Chinese and English materials, instead of homophonic ones, to increase phonological similarity among the materials within each trial to avoid the participants heavily relying on phonology. We tested two groups of Chinese-English bilinguals who have immigrated to the US before or after age 7. The two groups of early- and late-arrival bilinguals have better proficiency in English and Chinese, respectively. The findings from both groups revealed the robust advantage of dominant language, which replicated the L1 advantage in previous experiments. More important, both groups demonstrated better memory performance when the probe and the target were within the same language class than when they switched from one language to the other. That is, having either the probe or the target in participants’ dominant language did not result in better recall accuracy than when both the probe and the target were in the non-dominant language. Such results suggested that materials in different languages were retained separately in VSTM. Overall, the current findings from the probed recall task support the contribution from non-phonological representations to the effect of L1 advantage, and reveal the chunking/organizing principles based on language classes in Chinese-English bilinguals’ VSTM.
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