Multilingualism associated with less lateralization on free-viewing tasks than bilingualism and monolingualism

Abstract

A number of studies have shown decreased lateralization of linguistic as well as non-linguistic functions in multilingual and bilingual individuals compared to monolingual individuals. However, most of these studies used traditional laterality measures, such as visual field testing, which are rather artificial and strictly controlled laboratory tests that are dissimilar to how we view things in the real world. The present study used a free-viewing paradigm to explore mono, bi, and multilingual group differences in lateralization of non-linguistic functions, to determine if previous findings generalize to more naturalistic viewing conditions. Twelve monolingual, 10 bilingual, and 6 multilingual participants completed a language history questionnaire, four free-viewing laterality tasks (3 visuospatial, 1 emotional chimeric faces), two executive function tasks, and a demographics and handedness questionnaire. One-sample t-tests showed that the monolingual and bilingual groups had significant leftward biases for all of the laterality tasks, but the multilingual group did not demonstrate any biases. One-Way ANOVAs showed that there were significant differences between the bilingual and multilingual groups on the bias scores for two of the spatial laterality tasks, and the difference between the monolingual and multilingual groups approached significance on one. These results extend the current literature by showing less lateralization in multilingual individuals on more naturalistic free-viewing tasks, but surprisingly did not show differences between mono and bilingual individuals. Results should be interpreted with caution, however, as the sample sizes of the language groups were low and participants spoke a variety of languages which could have added variance.