The independent effects of phonotactic probability and neighbourhood density on lexical acquisition by preschool children

Abstract

The goal of this research was to disentangle effects of phonotactic probability, the likelihood of occurrence of a sound sequence, and neighborhood density, the number of phonologically similar words, in lexical acquisition. Two word learning experiments were conducted with 4-year-old children. Experiment 1 manipulated phonotactic probability while holding neighborhood density and referent characteristics constant. Experiment 2 manipulated neighborhood density while holding phonotactic probability and referent characteristics constant. Learning was tested at two time points (immediate vs. retention) in both a naming and referent identification task, although only data from the referent identification task were analyzed due to poor performance in the naming task. Results showed that children were more accurate learning rare sound sequences than common sound sequences and this was consistent across time points. In contrast, the effect of neighborhood density varied by time. Children were more accurate learning sparse sound sequences than dense sound sequences at the immediate test point but accuracy for dense sound sequences significantly improved by the retention test without further training. It was hypothesized that phonotactic probability and neighborhood density influenced different cognitive processes that underlie lexical acquisition. Keywords phonotactic probability; neighborhood density; lexical acquisition; vocabulary Models of spoken word recognition and production typically incorporate three types of representations: phonological, lexical, and semantic (e.g., Dell, 1988;Gupta & MacWhinney, 1997;Levelt, 1989;Luce, Goldinger, Auer, & Vitevitch, 2000;Magnuson, Tanenhaus, Aslin, & Dahan, 2003;McClelland & Elman, 1986;Norris, 1994). The phonological representation corresponds to information about individual sounds, with models varying in the specific sound unit chosen (e.g., phonetic features, context specific allophones, phonemes). Assuming a phoneme unit of representation, the phonological representation of a word such as "seal" would consist of three separate sound units, namely / s/, /i/, and /l/. The lexical representation corresponds to the whole-word form as a single unit. Thus, the lexical representation of "seal" would be a single lexical unit, specifically / sil/. Finally, the semantic representation corresponds to the meaning of the word, which for "seal" would include information such as "ocean mammal with webbed flippers."Correspondence should be addressed to: Holly Storkel, Ph.D., Associate Professor, Department of Speech-Language-Hearing: Sciences and Disorders, University of Kansas, 3001 Dole Human Development Center, 1000 Sunnyside Avenue, Lawrence,. 785-864-3974 (fax). hstorkel@ku.edu. NIH Public Access Author ManuscriptLang Cogn Process. Author manuscript; available in PMC 2012 January 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptRecent studies of adult and child spoken word recognition and production suggest that formrelated variables influence ret...

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

“…Sound sequences in words with high density are hypothesized to be easier to hold in working memory than those with low density because of the support from the many existing lexical representations in long-term memory. This leads to the creation of a more accurate and detailed new lexical representation in long-term memory for high-density as compared with low-density novel words (Storkel & Lee, 2011;Storkel et al, 2006). These findings present robust evidence that the effects of phonotactic probability and lexical density on word learning are independent.…”

“…Specifically, adults learned more words with low phonotactic probability sound sequences than words with high phonotactic probability sound sequences when learning was measured via partially correct responses, which was assumed to index triggering. Words with low phonotactic probability are presumably more easily recognized as new words, triggering word learning efficiently (Storkel, 2009;Storkel et al, 2006;Storkel & Lee, 2011), because they sound less like other known words, whereas words with high phonotactic probability sound very similar to known words (Frisch, Large, & Pisoni, 2000;Vitevitch et al, 1997). That is, a new word may be mistaken for a known word when phonotactic probability is high, failing to trigger learning of the new word.…”

“…These two stages of word learning (triggering and configuration) have been distinguished in prior word learning studies by examining how word learning (1) unfolds over time (e.g., Storkel & Lee, 2011), (2) changes across partially versus fully correct responses (e.g., Storkel et al, 2006), or (3) differs in distinct tasks (e.g., Pittman & Schuett, 2013). Specifically, in the study by Storkel and Lee (2011), participants were exposed to novel words multiple times at a maximum of six training-testing cycles over 2 days.…”

“…Specifically, in the study by Storkel and Lee (2011), participants were exposed to novel words multiple times at a maximum of six training-testing cycles over 2 days. Word learning following few exposures was assumed to tap triggering, whereas word learning following many exposures was assumed to tap configuration.…”

Enhanced recognition and recall of new words in 7- and 12-year-olds following a period of offline consolidation

“…Although 2-year-old children have shown incremental processing of spoken words (Swingley, Pinto, & Fernald, 1999), and children as young as four have been found to exhibit effects of neighborhood density and phonotactic probability (Storkel & Hoover, 2011;Storkel & Lee, 2011), the extent to which children show fully adult-like lexical competition effects between phonologically-similar items remains unclear (Sekerina & Brooks, 2007). Evidence from studies using lexical decision, repetition, and gating tasks suggests that lexical competition effects emerge over development, with the size of the competition effects depending on chronological age and the age at which the lexical items have been acquired (Garlock, Walley, & Metsala, 2001;Metsala, Stavrinos, & Walley, 2009;Metsala & Walley, 1998;Munson, Swenson, & Manthei, 2005;Walley, 1993).…”