Can lower inhibitory control lead to better second language phonological contrast learning?

Inhibitory control, a domain-general cognitive function involved in selectiveattention, has been linked to individual differences in second language (L2) learning. However, previous research on its role in L2 phonological learning has yielded mixedfindings. To clarify this relationship, the present study investigates how individualdifferences in inhibitory control relate to L2 speech learning, targeting intermediateKorean learners of English. Twenty-four participants completed five days ofcomputer-based auditory training on two English vowel contrasts (/ɪ/-/i/ and /ʊ/-/u/). Inhibitory control was measured using the Stroop task. Participants completed pre- andpost-tests with both trained and novel talkers, as well as everyday identification (ID)tests during the training phase. Results showed that learners with lower inhibitory control(i.e., higher Stroop scores) demonstrated greater improvement over training andincreased use of spectral cues—primary acoustic dimension for the target contrasts—when identifying English vowels. These learners also generalized their learning on howto use spectral cues to stimuli from a novel talker. This study suggests that lower(reduced) inhibitory control, possibly allowing for a broader focus of attention, mayfacilitate a more successful shift from using duration to spectral cues. This is particularlyrelevant in contexts like Korean EFL education, where learners are often instructed torely on durational differences between the target English vowels.