The Effects of Phonotactic Probability and Neighborhood Density on Adults' Word Learning In Noisy Conditions

Abstract

Purpose: Noisy conditions make auditory processing difficult. This study explores whether noisy conditions impact the effects of phonotactic probability (the likelihood of occurrence of a sound sequence) and neighborhood density (phonological similarity among words) on adults’ word learning. Method: Fifty-eight adults learned nonwords varying in phonotactic probability and neighborhood density in either an unfavorable (0dB Signal-to-Noise Ratio, SNR) or a favorable (+8dB SNR) listening condition. Word learning was assessed in a picture naming task by scoring the proportion of phonemes named correctly. Results: The unfavorable 0dB SNR condition showed a significant interaction between phonotactic probability and neighborhood density in the absence of main effects. Specifically, adults learned more words when phonotactic probability and neighborhood density were both low or both high. The +8dB SNR condition did not show this interaction. These results were inconsistent with those from a prior adult word learning study under quiet listening conditions that showed main effects of word characteristics. Conclusion: As the listening condition worsens, adult word learning benefits from a convergence of phonotactic probability and neighborhood density Clinical implications are discussed for potential populations who experience difficulty with auditory perception or processing making them more vulnerable to noise.