Proceedings of the Annual Meeting of the Cognitive Science Society

Successful language learning requires a dynamic balance between declarative and procedural mechanisms, yet individuals may engage them in less than optimal ways. The goal of the current experiment was to determine whether transcranial direct current stimulation (tDCS) can tip the balance, specifically facilitating declarative or procedural learning. Seventy-nine subjects (31 no stimulation, 16 sham stimulation, 16 temporal, 16 frontal) completed an artificial grammar learning task followed by a two-alternative forced- choice test measuring sensitivity to the underlying grammar (procedural) versus the surface form (declarative). The pattern of results is consistent with separate engagement of declarative and procedural systems. Left temporal stimulation resulted in higher selection of strings with familiar surface features. In contrast, frontal stimulation resulted in a slower learning trajectory and more frequent selection of grammatical letter strings. We conclude that tDCS may be used to facilitate engagement of different learning systems required for language learning.