Graduation Year


Document Type




Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Communication Sciences and Disorders

Major Professor

Ruth Huntley Bahr, Ph.D.

Committee Member

Stefan A. Frisch, Ph.D.

Committee Member

Amanda Huensch, Ph.D.

Committee Member

Catherine Rogers, Ph.D.


Adult Learners, Executive Function, Phoneme Category Development, Statistical Learning


Why are some people better at learning new languages than others? There is a rich body of research examining this issue from multiple perspectives and at all levels of language. This study attempts to add to that knowledge at the most fundamental level of language by examining potential influences on the learning of novel phoneme contrasts. The purpose of this study was to explore whether individual differences in attentional capabilities would help adults learn a non-native phonological contrast, and whether providing explicit directions that would guide the learners’ attention could help boost their performance. VCV recordings of the Thai /p/ and /b/ phonemes, which are often both heard as /b/ by English speakers, were provided by four native Thai speakers. A total of 57 monolingual English-speaking adults completed the study through the Gorilla online experimental platform ( The Attention Network Test (ANT; Fan, et al, 2002) was used to assess the three attentional networks: Alerting, Orienting, and Executive Function. To teach them the Thai /p/ and /b/ contrast, the participants underwent a statistical learning paradigm in which they had to match the sound they heard to an image on the screen. The paradigm consisted of a 40-question pretest, 480-trial learning phase, and 40-question posttest. Approximately half of the participants (n=30) were given explicit instruction on what to listen for prior to the learning phase. The other participants (n=27) were told to listen carefully but were given no specific direction. Generalized linear models (GLM) were fit to predict the participants’ posttest scores from their ANT subscores and their experimental group. A linear mixed effects model was also fit to describe the participants’ performance in each block during the learning phase. The results of the GLM showed significant interactions between Executive Function and experimental group (p=0.0398) and significant main effects of Executive Function (p=0.0209). The linear mixed effects model showed a significant three-way interaction between Executive Function, block, and experimental group (p=0.00363) and a significant two-way interaction between Executive Function and block (p=0.00567). Taken together, these results imply that individuals who are better able to control their attentional focus are better able to learn novel phoneme contrasts regardless of instruction. In addition, individuals with better Executive Function abilities seem to be able to benefit more from explicit instructions as to where to direct their attention, learning the target contrast more quickly and performing better on perceptual tasks.