In my work on bilingualism and neurocognitive adaptation, I treat language experience as set of interrelated continua, including language entropy, sheer amount of exposure, and age of language acquisition. In a series of publications, I found that these aspects jointly predict language proficiency, measured through self-report questionnaires and experimental tasks (e.g., verbal fluency). People with high degrees of L2 usage, high language entropy, or who acquired the two languages early in life tended to exhibit higher proficiency (Gullifer et al., 2021; Gullifer & Titone, 2020). These findings provide core validation for these bilingual experience features, including language-related uncertainty, and analytical methods that treat these factors jointly and continuously.
Below, you can watch a four-minute presentation on language entropy and proficiency (presented at AMLaP 2020 and Psychonomics 2020). You can also check out the project on OSF.
In a related line of work, I applied this approach to study brain organization and executive control. I found that age of language acquisition and language entropy predict the resting-state connectivity of unique brain networks involved in control (Gullifer et al., 2018), replicating and extending earlier work from the Klein lab at the Montréal Neurological Institute (Berken et al., 2016). While early age of acquisition predicted greater frontal connectivity, high language entropy predicted greater connectivity among a broad network of areas see. Connectivity in these areas further predicted individuals’ goal-maintenance and proactive control abilities measured by an AX-continuous performance task.
One might ask how replicable these neurocognitive findings are, given that they rely on small samples of participants. My ongoing work suggests that the results replicate with larger samples. For example, I found that the behavioral results replicated sample of over 400 multilinguals (Gullifer & Titone, 2021).
Below, you can watch a 15-minute talk on language entropy and proactive control (presented at Psychonomics 2020). You can also check out the project on OSF.
It appears that attention to goal-relevant cues may be important for high entropy bilinguals who must rapidly discover what language will come next in uncertain language situations so they can identify and maintain goal-relevant attentional information.