EXPRESS: Short-Term Memory in Following Spoken Instructions in a Second Language.

This study examined the hypothesis that use of a second language (L2) adds cognitive load to everyday short-term memory tasks even for fluent speakers. Persian-English bilingual participants (N = 36) followed sequences of five verbal instructions in first and second language. Recall was verbal or by enactment on a computer screen. Working memory capacity, phonological short-term memory and L2 learning and use variables were explored as covariates. The study replicated previous findings of better recall accuracy for enacted instructions compared to verbally recalled ones. There was a disadvantage for remembering instructions that had been presented in L2 specifically when recall was by enactment but not when it was verbal. Phonological short-term memory scores (L2 pseudoword repetition accuracy) were overall high and did not significantly predict accuracy of instruction enactment. Working memory span (operation span) was poorer in L2, and L1 and L2 span correlation was low. Only L1 span showed a non-significant trend to predict enactment memory. We conclude that L2 input can add cognitive load on the working memory system in an instruction-following task even for advanced learners. The load effect is seen especially when contextual cues and verbal instructions have to be processed together in enactment tasks.