Effects of Cognitive Load by Text Comprehension in a Second Language on Inferences: Evidence from Brain Activity Measurements

Abstract

When using a second language (L2), a greater amount of cognitive resources are consumed than when using a first language (L1). As a consequence, a smaller amount of resources can only be allocated to thinking processes, which often results in a decline of performance in thinking tasks. To examine this effect, we measured the activities of the frontal cortex while performing an inference task using functional near-infrared spectroscopy (fNIRS). L1 English users and L2 English learners (upper intermediate level) read an English text and then answered low- and high-difficulty inference questions about the text. In the high-difficulty condition, the L1 group showed a higher level of activity in the right front area than the L2 group. Given that inferences have been reported to show right hemisphere superiority, it could be suggested that the inference processing was not as high in the L2 learners as in the L1 speakers.