Serial memory mechanisms in monolingual and bilingual speakers

Aims and objectives: Recent findings suggest enhanced phonetic and phonological learning ability in bilinguals compared with monolinguals. While other cognitive differences between these two groups have been identified in the past, the most frequently investigated mechanism potentially underlying them has been executive function. When considering phonetic and phonological learning, however, we are faced with greater involvement of sensorimotor mechanisms, since audition, perception, and articulation are all important components in the learning of new patterns of pronunciation. The present study investigates memory mechanisms, with a focus on auditory sensory memory, in these two groups of speakers. Methodology: An adaptive digit span task with suffix effect was administered to two groups of speakers (bilinguals and monolinguals). Data and analysis: The two groups were compared in terms of accuracy rates (overall and by serial position), maximum digit span reached, and the proportion of participants who reached the highest list length. Findings/conclusions: The results show that bilinguals have longer digit spans and demonstrate higher accuracy compared with monolinguals for all serial positions inside every list length, suggesting an advantage not only in terms of recently heard items (i.e., recency effect, attributable to auditory sensory mechanisms) but also for the items heard in the beginning of longer list lengths (i.e., primacy effect, attributable to working memory). Originality: The role of sensory mechanisms in language learning, in particular auditory sensory (echoic) memory, was posited to have been underestimated to date. The current study addresses this gap by investigating alternative mechanisms that could support differences in behavior resulting from language experience of various types. Significance/implications: The connection between auditory sensory memory and linguistic experience suggests that sensory mechanisms are involved in some of the observed cognitive differences between bilinguals and monolinguals. In particular, sensorimotor mechanisms might at least partially account for more effective phonetic and phonological learning in bilinguals. The current study thus sheds more light on the coupling between cognitive and sensory functions.