Effects of Multitalker Input and Instructional Method on the Dimension-Based Statistical Learning of Syllable-Tone Combinations: An Eye-Tracking Study

To test the effects of talker variability and explicit instruction on the statistical learning of lexical tone, 80 monolingual English listeners were taught an artificial language that mimicked Mandarin's asymmetric distribution of syllable-tone co-occurrences. Training stimuli consisted of either speech from one talker or speech from four talkers. Participants were either never instructed or explicitly taught associations between phonemes (CVs), tones, and nonce symbols across four consecutive days. Learning was assessed by the accuracy of mouse clicks and eye movements to visual nonce symbols. Critical trials induced competition between the target symbol, which matched the acoustic input, and a competitor symbol that had a statistically more probable tone (but mismatched the acoustic input). Eye fixations indicated that participants were sensitive to syllable-tone co-occurrence probabilities even without explicit instruction of tone. The degree to which statistical knowledge was used to recognize words appeared to increase when participants processed more variable speech.