Authors

Evan HareFollow

Document Type

Open Access Thesis

Embargo Period

3-1-2018

Degree Program

Neuroscience & Behavior

Degree Type

Master of Science (M.S.)

Year Degree Awarded

2017

Month Degree Awarded

September

Advisor Name

Lisa Sanders

Abstract

Learning environment has been proposed to be a cause of age of acquisition effects in second language acquisition. Explicit learning in adults is linked to fast initial gains but poorer ultimate attainment whereas implicit learning in children requires more input but leads to greater proficiency in the long run. The current study used ERP measures to determine if explicit learning of a phonotactic pattern interferes with implicit learning of that same pattern in adults. Listeners were told to figure out the pattern of consonants that can go together in a word by listening to 16 CVCV nonsense words in which the two consonants all matched in voicing or never matched in voicing.

Listeners rated novel items that fit the pattern presented in training as far more likely to fit the rule than novel items that violated that pattern, indicating that they did indeed learn the pattern. For participants who heard the voicing-mismatch language, novel items that violated the pattern elicited a larger negativity 200-400 ms after onset compared to novel items that fit the pattern. This effect was entirely distinct from what was previously observed under implicit learning conditions. Further, three patterns of data suggest that difficult explicit learning of a phonotactic pattern decreased language learning. First, differences in N400 amplitude across training blocks were reduced compared to what was observed with implicit learning. Differences in N400 amplitude in response to trained and novel items were limited to the more easily learned matched-voicing language. Second, the ERP index of implicit phonotactic learning, a larger Late Positive Component (LPC) in response to novel items that violate compared to fit the pattern, was absent under explicit learning conditions. Third, and supporting the idea that an absence of an LPC effect indicates an absence of implicit learning, the only hint of an LPC-like effect was evident for the more easily learned matched-voicing pattern.

These patterns of data suggest that, at least for patterns that native speakers have exclusively implicit knowledge of, challenging explicit learning can interfere with other aspects of language learning. Adults who approach second-language acquisition with class-room style explicit learning strategies may compromise implicit learning of complex patterns that are necessary for higher levels of ultimate proficiency.

First Advisor

Lisa Sanders

Available for download on Thursday, March 01, 2018

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