Date of Graduation


Degree Type



College of Education and Human Services


Not Listed

Committee Chair

Kimberly Meigh

Committee Member

Kimberly Meigh


Purpose: The contextual interference (CI) effect is a motor learning phenomenon where learners experience difficulty during training resulting in poor performance; however, improved performance is observed in transfer conditions. Different variables elicit a CI effect, and the purpose of this study is to investigate whether phoneme (or sound) similarity may result in a CI effect during speech motor learning.

Method: The study included twenty-nine participants whose hearing and speech abilities were within the normal range. Participants were randomly assigned to one of two training sessions involving nonwords with either similar or dissimilar phonemes. Each training session included nonword repetition training with feedback, retention task where trained nonwords were repeated without feedback, and a transfer task where novel, untrained nonwords were repeated. Following the first training session, participants initiated the second training session with the opposite set of stimuli. Stimuli assignment was counterbalanced across participants. Analyses include perceptually rating accuracy of the nonword productions.

Results: Results suggest motor learning is influenced by the number of similar phonemes present in each nonword. This is suggestive of a CI effect due to phoneme similarity. Nonwords containing both similar and dissimilar phonemes initiated a learning effect. Additionally, training with dissimilar phonemes demonstrated the presence of a CI effect.

Conclusion: Training with dissimilar phonemes does initiate a CI effect, which should allow phonemic similarity to be considered a more prominent CI variable in motor learning. Clinicians should manipulate their target words to contain more dissimilar phonemes, induce the CI effect, and improve clinical outcomes.