Does high variability training improve the learning of non-native phoneme contrasts over low variability training? A replication.

• Phonetic training can enable learners to distinguish between non-native phonemes. • Seminal studies propose that high talker variability (HV) is key to generalisation. • We conducted a replication (N = 166) of seminal studies to test for such a HV benefit. • All evidence for a HV benefit was ambiguous, contradicting original findings. • Our study raises questions about the true size and robustness of the HV benefit. Acquiring non-native speech contrasts can be difficult. A seminal study by Logan, Lively and Pisoni (1991) established the effectiveness of phonetic training for improving non-native speech perception: Japanese learners of English were trained to perceive /r/-/l/ using minimal pairs over 15 training sessions. A pre/post-test design established learning and generalisation. In a follow-up study, Lively, Logan and Pisoni (1993) presented further evidence which suggested that talker variability in training stimuli was crucial in leading to greater generalisation. These findings have been very influential and "high variability phonetic training" is now a standard methodology in the field. However, while the general benefit of phonetic training is well replicated, the evidence for an advantage of high over lower variability training remains mixed. In a large-scale replication of the original studies using updated statistical analyses we test whether learners generalise more after phonetic training using multiple talkers over a single talker. We find that listeners learn in both multiple and single talker conditions. However, in training, we find no difference in how well listeners learn for high vs low variability training. When comparing generalisation to novel talkers after training in relation to pre-training accuracy, we find ambiguous evidence for a high-variability benefit over low-variability training: This means that if a high-variability benefit exists, the effect is much smaller than originally thought, such that it cannot be detected in our sample of 166 listeners. [ABSTRACT FROM AUTHOR]