Examining and reexamining the structure of Chinese-English bilingual memory

Modeling activation and effective connectivity of VWFA in same script bilinguals

Previous neuroimaging research revealed a small area in the inferior occipito-temporal cortex (VWFA), which seems to be involved in recognition of written words. The specialized response of the VWFA to words could result from repeated exposure to print in the course of functional fine-tuning of the brain. Research with bilingual speakers holds promise in helping to reveal response properties of the VWFA by assessing its sensitivity to language proficiency, word-form similarity, and meaning overlap across two languages. Using fMRI, we compared VWFA activity for cognate and homograph prime-target pairs in a group of fluent Spanish-English speakers. Cognates share form and meaning in two languages, while homographs only share form. Relative to baseline, the VWFA showed repetition suppression to pairs of homographs, but not to pairs of cognates, suggesting that this area is sensitive to word meaning. The different response to cognates and homographs was only observed when English was the prime language and Spanish was the target language. To help explain this result we compared patterns of effective connectivity between the VWFA and other parts of the reading network implicated in semantic and phonological processing. Our neural models showed that English targets engaged a direct ventral route from the VWFA to the frontal lobe and Spanish targets engaged an indirect dorsal route. Considering that frontal cortex has been implicated in semantic processing, a direct connection to this area could signal a fast and automatic access to meaning and would facilitate early semantic influences in visual word recognition.

Stroop effects in bilingual translation

In two experiments, bilinguals proficient in English and Spanish translated words from one language to the other. In each experiment, following the target word to be translated, distractor words were presented after a short (200-msec) or long (500-msec) stimulus onset asynchrony. In Experiment 1, the distractor words appeared in the language of production and were related to the meaning or form of the spoken translation. The results replicated past studies in demonstrating that semantically related distractor words produced Stroop-type interference, whereas form-related distractor words produced facilitation. In Experiment 2, the distractors appeared in the language of input and were related to the meaning or form of the target word itself. In contrast to the results of Experiment 1, there were only marginal effects of the distractors on translation performance. These results suggest that language cues related to the nature of the input in translation may serve to reduce competition among lexical competitors during lexicalization. The contrast between these results and those in bilingual picture-word interference studies provides important constraints for models of language production and for claims about the locus of language selection.

Lexical and conceptual processing in Chinese-English bilinguals: further evidence for asymmetry

According to the asymmetry model of bilingual representation (Kroll & Stewart, 1994), the first language (L1) lexicon is closely tied to an underlying conceptual memory, whereas second language (L2) items are mostly associated with their L1 equivalents. An outcome of this architecture is that L1-to-L2, or forward, translation must be mediated by the conceptual memory, whereas L2-to-L1 (backward) translation takes a direct lexical path. Some predictions derived from this hypothetical structure were tested in the present study, which took into account, through analysis of covariance, variations in response production time, concept retrieval time, and some other characteristics associated with the individual test items. Proficient Chinese-English bilinguals were tested on delayed production (Balota & Chumbley, 1985), picture naming, word translation, and category matching. The expected asymmetrical pattern of translation latencies (i.e., forward > backward) was demonstrated, although it could be statistically explained by the item characteristic of familiarity; matching an L1 item to a category name was faster than matching an L2 item, suggesting relatively strong L1 conceptual links. The present results are best accommodated by a form of asymmetry that allows for nondominant L2-concept linkage, the use of which is conditional upon the familiarity of the test item to the bilingual.