When speaking in just one language, bilinguals do not seem different from monolinguals. At other times bilinguals seem to be language acrobats, switching back and forth between languages, without apparent effort. Only on rare occasions do bilinguals produce a word in an unintended language - or cross-language intrusion errors (<1% Gollan et al., 2011; Poulisse, 1997), and perhaps for this reason intrusions have remained largely unexplored even though they hold potential to reveal the cognitive mechanisms fundamental to bilingual language control. The rarity of intrusion errors challenges an assumption that has become ubiquitous in bilingual research -that bilinguals face constant competition due to dual-language activation. We hypothesize that bilingual language control, including both the acrobatics associated with intentional language mixing, and the rarity of intrusion errors, reflects the joint operation of multiple control mechanisms including both language-specific and domain-general control mechanisms. The proposed studies will elicit intended and unintended language switches to investigate language-specific control mechanisms (Aim 1) including grammatical constraints, lexical accessibility, inhibitory links between translation equivalents, and error monitoring processes that rely on the language comprehension system. We hypothesize that bilinguals also rely on domain-general control mechanisms to achieve language selection, and investigate the possible roles of inhibition and attention for controlling single-language and mixed-language speech, the processing loci at which bilinguals use inhibition to maintain language selection, and contextual cues and strategies that improve language control by reducing switch costs and intrusion errors (Aim 2). Converging evidence for the classification of control mechanisms as language-specific versus domain-general will come from investigation of aging effects, and correlations with individual differences in measures of executive control (Aim 3). As we investigate factors that lead to more versus less effective ability to control language selection we develop new methods for studying speech errors using reading aloud with eye-tracking. The proposed work will establish test conditions that maximize bilingual proficiency, and will provide preliminary norms for young and aging bilinguals on a number of oft-used standardized tests. Broader questions addressed include the cognitive mechanisms underlying switching, deficits in cognitive aging, and how domain-general mechanisms function in concert with the language system to allow all speakers to resolve competition and produce error free speech.
Bilinguals are rapidly increasing in numbers, and perform significantly different from monolinguals on a number of tests commonly used for cognitive assessment, yet very little is known about how language and cognitive assessments should be adjusted to take these differences into account. The proposed studies will provide important information about how bilingualism affects language and cognitive processing, which types of bilingualism affect performance, which testing conditions allow bilinguals to function most fluently, and how these effects change as bilinguals become older. More generally the proposed studies will serve to develop theoretical models of bilingualism, the role of executive control in language processing, and normal aging related decline in language processing.
| Gollan, Tamar H; Goldrick, Matthew (2018) A switch is not a switch: Syntactically-driven bilingual language control. J Exp Psychol Learn Mem Cogn 44:143-156 |
| Gollan, Tamar H; Stasenko, Alena; Li, Chuchu et al. (2017) Bilingual language intrusions and other speech errors in Alzheimer's disease. Brain Cogn 118:27-44 |
| Li, Chuchu; Goldrick, Matthew; Gollan, Tamar H (2017) Bilinguals' twisted tongues: Frequency lag or interference? Mem Cognit 45:600-610 |
| Kleinman, Daniel; Gollan, Tamar H (2016) Speaking Two Languages for the Price of One: Bypassing Language Control Mechanisms via Accessibility-Driven Switches. Psychol Sci 27:700-14 |
| Gollan, Tamar H; Goldrick, Matthew (2016) Grammatical Constraints on Language Switching: Language Control is not Just Executive Control. J Mem Lang 90:177-199 |
