Emily Mather

There is widespread evidence that children display a mutual exclusivity response upon encountering new words. Children displaying this behaviour will select a novel, name‐unknown object in response to a novel label, rather than a familiar, name‐known object. The mutual exclusivity response has been viewed as a means of fast‐mapping vocabulary—enabling the retention of new words with minimal and incidental exposure. Thus, it may play an important role in driving early vocabulary growth. Yet, while the mutual exclusivity response may initially guide the correct choice of a novel word's referent, it does not necessarily result in retention for even brief durations. In this pre‐registered meta‐analysis, we examined the evidence for the retention of novel noun mappings disambiguated through the mutual exclusivity response. While a large effect size was observed for the mutual exclusivity response, consistent with past research, there was a smaller effect for subsequent retention—which was substantially attenuated by Bayesian publication bias correction. Our findings are consistent with models of word learning in which referent selection is not governed by the same processes underlying referent retention.

Previous studies showed that word learning is affected by children's existing knowledge. For instance, knowledge of semantic category aids word learning, whereas a dense phonological neighbourhood impedes learning of similar‐sounding words. Here, we examined to what extent children associate similar‐sounding words (e.g., rat and cat) with objects of the same semantic category (e.g., both are animals), that is, to what extent children assume meaning overlap given form overlap between two words. We tested this by first presenting children (N = 93, Mage = 22.4 months) with novel word‐object associations. Then, we examined the extent to which children assume that a similar sounding novel label, that is, a phonological neighbour, refers to a similar looking object, that is, a likely semantic neighbour, as opposed to a dissimilar looking object. Were children to preferentially fixate the similar‐looking novel object, it would suggest that systematic word form‐meaning relations aid referent selection in young children. While we did not find any evidence for such word form‐meaning systematicity, we demonstrated that children showed robust learning for the trained novel word‐object associations, and were able to discriminate between similar‐sounding labels and also similar‐looking objects. Thus, we argue that unlike iconicity which appears early in vocabulary development, we find no evidence for systematicity in early referent selection.

Much of our basic understanding of cognitive and social processes in infancy relies on measures of looking time, and specifically on infants’ visual preference for a novel or familiar stimulus. However, despite being the foundation of many behavioral tasks in infant research, the determinants of infants’ visual preferences are poorly understood, and differences in the expression of preferences can be difficult to interpret. In this large-scale study, we test predictions from the Hunter and Ames model of infants' visual preferences. We investigate the effects of three factors predicted by this model to determine infants’ preference for novel versus familiar stimuli: age, stimulus familiarity, and stimulus complexity. Drawing from a large and diverse sample of infant participants (minimum expected sample size N = 1,280), this study aims to provide empirical evidence for a robust and generalizable model of infant visual preferences, leading to a more solid theoretical foundation for understanding the mechanisms that underlie infants’ responses in common behavioral paradigms. Moreover, we hope that our findings will guide future studies that rely on infants' visual preferences to measure cognitive and social processes.

In a wide ranging article in this journal, Byers‐Heinlein et al. (2022) make a persuasive case for paying close attention to reliability in developmental research. They focus on measurement reliability, which indexes how well individuals can be ranked across repeated measurements. We highlight the importance of measurement precision as a complement to understanding measurement reliability. We describe how this more absolute type of reliability can be quantified by the within‐participant standard deviation across trials, also known as the standard error of measurement (SEM). We outline how reporting and understanding measurement precision can play a key role in achieving the ‘six solutions’ for improving reliability in developmental research offered by Byers‐Heinlein et al.

There is an ongoing debate over the extent to which language development shares common processing mechanisms with other domains of learning. It is well-established that toddlers will systematically extend object labels to similarly-shaped category exemplars (e.g., Landau, Smith, & Jones, 1988; Markman & Hutchinson, 1984). However, previous research is inconclusive as to whether young children will similarly extend factual information about an object to other category members. We explicitly contrast facts varying in category relevance, and test for extension using two different tasks. Three- to four-year-olds (N = 61) were provided with one of three types of information about a single novel object: a category-relevant fact (‘it’s from a place called Modi’), a category-irrelevant fact (‘my uncle gave it to me’), or an object label (‘it’s called a Modi’). At test, children provided with the object name or category-relevant fact were significantly more likely to display systematic category extension than children who learnt the category-irrelevant fact. Our findings contribute to a growing body of evidence that the mechanisms responsible for word learning may be domain-general in nature.

Across a series of four experiments with 3- to 4-year-olds we demonstrate how cognitive mechanisms supporting noun learning extend to the mapping of actions to objects. In Experiment 1 (n = 61) the demonstration of a novel action led children to select a novel, rather than a familiar object. In Experiment 2 (n = 78) children exhibited long-term retention of novel action-object mappings and extended these actions to other category members. In Experiment 3 (n = 60) we showed that children formed an accurate sensorimotor record of the novel action. In Experiment 4 (n = 54) we demonstrate limits on the types of actions mapped to novel objects. Overall these data suggest that certain aspects of noun mapping share common processing with action mapping and support a domain-general account of word learning.