Word knowledge in six- to nine-month-old Norwegian infants? Not without additional frequency cues.

Natalia Kartushina,Julien Mayor

doi:10.1098/rsos.180711

Abstract

The past 5 years have witnessed claims that infants as young as six months of age understand the meaning of several words. To reach this conclusion, researchers presented infants with pairs of pictures from distinct semantic domains and observed longer looks at an object upon hearing its name as compared with the name of the other object. However, these gaze patterns might indicate infants' sensibility to the word frequency and/or its contextual relatedness to the object regardless of a firm semantic understanding of this word. The current study attempted, first, to replicate, in Norwegian language, the results of recent studies showing that six- to nine-month-old English-learning infants understand the meaning of many common words. Second, it assessed the robustness of a ‘comprehension’ interpretation by dissociating semantic knowledge from confounded extra-linguistic cues via the manipulation of the contingency between words and objects. Our planned analyses revealed that Norwegian six- to nine-month-old infants did not understand the meaning of the words used in the study. Our exploratory analyses showed evidence of word comprehension at eight to nine months of age—rather than from six to seven months of age for English-learning infants—suggesting that there are cross-linguistic differences in the onset of word comprehension. In addition, our study revealed that eight- to nine-month-old infants cannot rely exclusively on single extra-linguistic cues to disambiguate between two items, thus suggesting the existence of early word-object mappings. However, these mappings are weak, as infants need additional cues (such as an imbalance in frequency of word use) to reveal word recognition. Our results suggest that the very onset of word comprehension is not based on the infants' knowledge of words per se. Rather, infants use a converging set of cues to identify referents, among which frequency is a robust (pre-semantic) cue that infants exploit to guide object disambiguation and, in turn, learn new words.

Highlights

IntroductionWhile for decades, researchers believed that infants wait until they are approximately eight months of age to understand their first words, recent studies suggest that children know the meaning of several common words as early as from six months of age [1,2,3,4,5]
Previous research [1] has already provided evidence that infants’ early word comprehension of semantically related items is fragile: six-month-old infants fail to disambiguate between items when the semantic cues are congruent with both items, suggesting that they rely on semantic cues to disambiguate between items. Is it possible that six- to nine-month-old infants use other available cues to disambiguate between items, in particular, cues that have been shown to help infants learn words; i.e. the context of word use and its frequency? In the current study, we tested these two alternative explanations for the finding that infants know the meaning of multiple words, as reported in BS12: we examined whether six- to nine-month-old infants can rely on non-semantic, extra-linguistic cues, i.e. frequency and context of use, to disambiguate between objects
The results revealed that all participants attended the targets upon their appearance on the screen, suggesting that they were engaged in the task and fixated the target when it appeared on the screen

Summary

Introduction

While for decades, researchers believed that infants wait until they are approximately eight months of age to understand their first words, recent studies suggest that children know the meaning of several common words as early as from six months of age [1,2,3,4,5]. At the age of six months, infants show comprehension of words referring to salient social figures in their lives, i.e. From the same age, infants start showing comprehension for some concrete objects, for example, body parts ‘hand’ and ‘feet’ [5] or food-related items [2], and, some months later (at 9–10 months), their comprehension extends to more abstract words (e.g. all-gone and hi [3]), as revealed by longer looks to the target picture upon hearing its label when compared with the distractor [3,4]

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