Word processing before explicit attention: using the gaze-contingent boundary paradigm in L2 reading research

Eye-movement studies investigating second language (L2) word processing during reading are growing exponentially. However, what information L2 readers are able to process parafoveally is a less researched topic. The gaze-contingent boundary paradigm (Rayner, 1975) allows researchers to manipulate visual information in an upcoming word during reading, tapping into real-time word processing without awareness. This article provides an overview of experimental studies of parafoveal word processing in reading, followed by a methodological review of the use of the boundary paradigm in L2 and bilingual research. We synthesize key methodological details (including preview type, eye-movement measures) and findings of 15 experiments that met our search criteria, concluding that the parafoveal preview effect observed when reading in the first language is also present in L2 reading. We propose how the gaze-contingent boundary paradigm can be used to study L2 lexical knowledge and factors that affect its development. Finally, we provide advice and instructions for designing and conducting boundary paradigm experiments.