Co-registration of EEG and eye-tracking in psycholinguistics and bilingualism research

Eye-tracking and electroencephalogram (EEG) recordings provide a window into the human mind. Combining both methods through co-registration offers a powerful and innovative approach for examining how cognitive and neural processes unfold in real time. While both EEG and eye-tracking have independently advanced our understanding of bilingual language processing, co-registration research in the field of bilingualism remains scarce. Given the potential of co-registration methodology to integrate multiple sources of information, this article provides a theoretically and empirically informed perspective on how it can be applied to bilingualism research. Drawing on findings from EEG and eye-tracking studies on bilingual language processing, as well as co-registration research in reading, we identify key areas of bilingualism, such as crosslinguistic activation and inference revision, where co-registration can help address existing gaps. We also discuss several methodological challenges associated with co-registration and offer practical recommendations for its effective implementation in future studies. We conclude that co-registration can move research on bilingual language processing toward a more integrated perspective, one that better captures the dynamic interplay between language and cognition.