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 influence 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 (0-dB signal-to-noise ratio [SNR]) or a favorable (+8-dB SNR) listening condition. Word learning was assessed using a picture naming task by scoring the proportion of phonemes named correctly. Results: The unfavorable 0-dB SNR condition showed a significant interaction between phonotactic probability and neighborhood density in the absence of main effects. In particular, adults learned more words when phonotactic probability and neighborhood density were both low or both high. The +8-dB SNR condition did not show this interaction. These results are inconsistent with those from a prior adult word learning study conducted under quiet listening conditions that showed main effects of word characteristics. Conclusions: 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.

Adult Word Learning as a Function of Neighborhood Density

“…Stimuli were divided at the median value for ND: Words above the median were classified as dense, and words at or below the median value were classified as sparse. This methodology is consistent with related work (e.g., Han et al 2016;Storkel 2001). Sparse words had a mean ND of seven neighbors (sd = 2.94; range = 3-10), and dense words had a mean ND of 23 neighbors (sd = 7.39; range = 16-32).…”

“…Previous similar studies have reported a greater advantage of learning dense nonwords rather than sparse nonwords. However, many of these studies administered tasks originally designed for use with young, preliterate children (Freedman 2015;Han et al 2016;Storkel et al 2006;Dumay and Gaskell 2006;Gaskell and Dumay 2003), which are not ecologically valid for typical adult word learning contexts. This is particularly true in higher education, where adults acquire new lexical items in the context of related information.…”

“…Additionally, Marzilli, Delello, Marmion, and McWhorter (Marzilli et al 2015) reported that nearly 80% of college students learn information in the classroom through the use of Microsoft PowerPoint. And yet, previous studies of this nature have relied on either teaching adults simple pairings of nonwords and objects (Rastle et al 2011;Saletta et al 2016a;Storkel et al 2014;Vitevitch et al 2014), or using a narrative created for young, preliterate children (Freedman 2015;Han et al 2016;Storkel et al 2006). In order to more validly assess how ND impacts adult word learning, if at all, a task must first be created to mirror a typical learning experience.…”

The Influence of Misarticulations on Children's Word Identification and Processing

“…An additional factor that potentially could influence children's selections was the possibility that, although features were controlled, the two substitutes were phonetically similar to the accurate phonemes. To ensure that this was not a factor, we determined the confusability between the accurate initial phoneme and each misarticulated phoneme, in accordance with the procedures in Han, Storkel, Lee, and Cox (2016). From the tables in Wang and Bilger (1973), we found the proportion of times each accurate phoneme was confused with the misarticulated phoneme.…”

A Study on the Korean-Version of the Youth Attitudes toward Noise Scale

“…A word learning study by Han, Storkel, Lee, and Cox (2016) revealed that word learning by young adults requires multiple cues of word characteristics to facilitate word learning in noisy learning environments compared to quiet environments.…”