Seminal research which indicates that bilingualism leads to enhanced executive control (Bialystok, Craik, Green & Gollan, 2009; Bialystok, Craik & Luk, 2012) has recently been challenged (de Bruin, Treccani & Della Sala, 2014; Hilchey & Klein, 2011; Paap & Greenberg, 2013). We suggest that this discrepancy in findings is attributable to differences between bilinguals. Although the present results showed no significant differences in executive control between the monolinguals and bilinguals, those bilinguals who used their L2 more frequently in their daily lives were significantly more likely to evidence enhanced executive control over those who rarely used their L2.

This study investigates the role of age of acquisition (AoA) on the bilingual mental lexicon. Four groups of participants were tested: (i) English native speakers with minimal exposure to French; (ii) late English–French bilinguals; (iii) early English–French bilinguals; and (iv) simultaneous English–French bilinguals. We used a masked priming paradigm to investigate early, automatic lexical processing at the semantic level by testing both a within-language semantic condition and a cross-language translation condition. AoA was investigated both through group effects and a correlation analysis. We found significant translation priming effects for the simultaneous and early bilinguals only, and a significant correlation between AoA and translation priming effects. Due to the matched L2 proficiency of the early and late bilinguals, these results support our hypothesis that an early AoA, regardless of L2 proficiency, is crucial in order to find the L2-to-L1 priming effects that have often been elusive in recent studies.

Cross-language priming is a widely used experimental paradigm in psycholinguistics to study how bilinguals’ two languages are represented and organized. Researchers have observed a number of interesting patterns from the priming effects of both translation equivalents and semantically related word pairs across languages. In this study, we implement a self-organizing neural network model, DevLex–II, to simulate these two types of priming effects across Chinese and English. Specifically, our model incorporates a computational mechanism for simulating spreading activation based on the distance between bilingual words in the semantic space. The model also considers additional factors that modulate priming effects, such as the initial activation level of the prime words and the degree to which the target word can be recognized. Our model reveals differences with respect to the priming effects as a function of bilingual type (early versus late L2 learners), directions of priming (L1 to L2 versus L2 to L1), and types of priming (translation versus semantic priming). These simulated differences are compared with empirical findings from previous studies and discussed in the light of interactive and developmental theories of bilingual lexical representation.