I am interested in second language (L2) acquisition, and the role of implicit learning through print exposure (i.e. lifelong reading experience). My research has focused primarily on how L2 learners acquire kinds of vocabulary which are difficult to learn explicitly, including formulaic language like collocations ("raise prices" as opposed to "lift prices") or idioms ("kick the bucket" meaning "to die"), or more functional language such as discourse connectives, which link separate clauses ("nevertheless", "whereas", "furthermore", etc.). These kinds of vocabulary tend to be challenging for L2 speakers, and this is likely because they require significant additional exposure in order to learn how they are used. Book language, or the kinds of language we encounter in books, is distinguished from other kinds of language exposure by its increased lexical richness and more advanced syntax. Additionally, it is likely that reading helps to attune speakers to what is "formulaic", and together, these features make reading a critical source of input for L2 acquisition. In this way, my work is rooted in the theoretical perspectives of cognitive linguistics and usage-based frameworks.

Another aspect of my research has focused on the psychometrics of print exposure. Print exposure is typically assessed through a proxy measure called the Author Recognition Test (ART), where participants see a list of names and indicate which they recognize as published authors. ART been extensively validated in native (L1) speakers and is associated with many component skills of reading, but concerns have been raised about its validity in L2 populations. In one study, an item response theory (IRT) analysis demonstrated that ART is less reliable in L2, as most author names on ART are unknown to L2 speakers (McCarron & Kuperman, 2021). At the same time, this group difference is not deterministic, as L2 speakers tend to increase their print exposure at a similar rate to natives throughout years of postsecondary education, showing they can close this experience gap over time (McCarron & Kuperman, 2022). The question, then, is if L2 speakers do not read enough in L2, or if they simply do not read the same authors as L1 speakers.

More recently, I have developed an alternative to ART for use in L2 populations. This task retains author names as the primary unit of measurement, but uses the logic of a semantic fluency task, where participants must list as many category members as possible within a set time limit. Several studies from my PhD demonstrated that this "Author Fluency Task" (AFT) outperforms ART as a predictor of L2 vocabulary knowledge in L1 French learners of English (e.g. McCarron et al., 2024). My hope is that AFT will offer a measure of print exposure which acknowledges that the variability in L2 experience is a "feature, not a bug".

Whereas my prior work focused on the importance of experience for language development, in my current position I have had the opportunity to explore the influence of heritable factors as well. Within the Hart Lab, we study the genetics of reading disability using large-scale, longitudinal twin datasets. The grant I am currently working on concerns gender differences in access to language intervention services in schools—although research samples show that boys and girls are nearly equivalent for reaching criteria for developmental language disorder (DLD), boys tend to receive service at a rate twice that of girls. This project will determine to what extent this difference in access is driven by true gender differences in language ability, as opposed to structural barriers and stereotypes which may prevent girls from being identified as early or as often as boys.