Word Frequency Is a Cue to Lexical Category for 8-Month-Old Infants

Abstract

Highlights d Eight-month-old infants use word frequency to categorize functors and content words d They allow substitutions for content words, processing them as an open class d But they do not accept novel functors, suggesting those constitute a closed class d They recognize the relative order of the two classes in their native language

8-month-old infants' ability to process word order is shaped by the amount of exposure

“…Importantly, here we test French-exposed infants. This population has been found to show a frequent-initial word order preference in a previous study (Marino et al, 2020) using exactly the same paradigm as here, similarly to our previous work with infants exposed to other functor-initial languages (e.g. Gervain et al, 2008;Gervain & Werker, 2013).…”

“…This issue was addressed in follow-up studies that demonstrated that infants expect the categories of frequent and infrequent words to have all the typical distinctive features of the categories of functors and content words, respectively. A recent study (Marino et al, 2020) demonstrated that after being exposed to the same artificial grammar as in Gervain et al (2008), French 8-month-olds expected infrequent words to belong to open classes, like content words, readily accepting novel tokens in the X and Y positions, whereas they considered frequent items as belonging to closed classes, like functors, accepting no novel items, and used only the frequent words to compute word order, suggesting they are familiar with the grammatical function of functors (Marino et al, 2020). This suggests that infants treat the categories established on the basis of frequency to behave differently with respect to the extensibility of their classes, similarly to functors and content words in natural language.…”

“…In a set of artificial grammar-learning studies using the headturn preference procedure (HPP) it has been demonstrated that sensitivity to the relation between word frequency, phonology and word order is established already pre-lexically (e.g. Gervain et al, 2008;Bernard & Gervain, 2012;Gervain & Werker, 2013;Marino et al, 2020). In these studies, infants were familiarized with artificial grammars containing a strict alternation of frequent and infrequent words, mimicking functors and content words, respectively and were then tested on their looking time preferences when exposed to test items presenting opposite word orders.…”

“…The artificial grammars that were used in the studies mentioned above (Gervain et al, 2008;Bernard & Gervain, 2012;Gervan & Werker, 2013;Marino et al, 2020), shared a common basic structure. Specifically, frequent words and infrequent words were presented with a 1:9 frequency ratio.…”

“…Based on Gervain et al (2008) and Marino et al (2020), using similar artificial grammar learning paradigms as the current one, a power calculation to estimate the sample size was performed. In the two previous studies, an effect size (Cohen's d) of d = .524 was obtained.…”