Postersession 3
Poster #: 117
Topic: Speech and language (incl. deficits)
Friday, Sep 11, 2015
15:30-17:00
1st floor

Changes in MMR amplitude reflect fast phonetic learning in adult listeners

Kateřina Chládková1 & Paola Escudero2

1Amsterdam Center for Language and Communication, University of Amsterdam, Amsterdam, Netherlands
2MARCS Institute, University of Western Sydney, Surry Hills, Australia
k.chladkova@uva.nl

This study examined whether phonetic learning occurs automatically after a short exposure to a statistical distribution of speech sounds. We assessed the amplitude of the mismatch response (MMR) before and after 9 minutes of unattended distributional training. During training, twenty Spanish listeners were exposed to a bimodal distribution of sounds on the first-formant (F1) dimension: half of them listened to a distribution with a trough at low F1 values, and the other half with a trough at high F1 values (“low-boundary” and “high-boundary” groups, respectively). A pre-attentive oddball paradigm was presented before and after training: the Standard had an F1 value representative of the Spanish /i-e/ boundary, and two Deviants had values of Spanish /i/ “i-Deviant”, and /e/ “e-Deviant”. (Note that in training the Standard, i-Deviant, and e-Deviant all had the same probability of occurrence.) If listeners learned from the bimodal distributions they heard in training, the trained boundary locations should affect their pre-attentive discrimination of stimuli at post-test. Specifically, for the low-boundary group, Standard and e-Deviant should be perceived as one category and i-Deviant as the oddball, while for the high-boundary group, e-Deviant should be the oddball. Difference waves were computed as post-test minus pre-test responses to physically identical stimuli, and MMR quantified as the average absolute amplitude between 100 and 200ms after stimulus-onset. As predicted, i-Deviant yielded larger MMR than e-Deviant for the low-boundary group, and vice versa for the high-boundary group. This demonstrates that adults successfully learn to discriminate non-native vowel contrasts after short distributional training.