In the mind’s eye: Eye-tracking and multi-modal integration during bilingual spoken-language processing

The human language system integrates information from multiple sources and modalities. Bilinguals, who experience increased processing demands due to competition between their two languages, may be especially likely to rely on cues from multiple modalities. The cross-modal integration involved in language processing has been frequently studied using eye-tracking, an approach that can accommodate the simultaneous presence of both auditory and visual inputs. Eye-tracking research has demonstrated that bilinguals activate both of their languages in parallel (e.g., Spivey and Marian 1999; Weber and Cutler 2004), leading to competition both within (e.g., the English word �marker� competes with the phonologically similar word �marble�) and between (e.g., the English word �marker� competes with the Russian word �marka�) their two languages (Marian and Spivey 2003a, b). Interestingly, this competition arises even when languages do not share phonology (e.g., bimodal bilinguals; Shook and Marian 2012) and in the absence of explicit linguistic input (Chabal and Marian 2015), demonstrating the highly interactive nature of bilingual language processing. This interactivity in the language system yields changes to bilingual cognitive function. For example, bilinguals� need to control phonological competition is associated with enhanced executive control (Blumenfeld and Marian 2011), and their experience suppressing information from the non-target language improves their ability to learn novel vocabulary (Bartolotti and Marian 2012). We conclude that multi-modal investigations of language processing such as those employing eye-tracking are not only ecologically valid, as they closely resemble real-world multi-modal situations, but also can demonstrate how language interacts with other cognitive and perceptual functions in a non-modular mind.