Publications

Abstract

There is a growing interest in the use of webcams to conduct eye-tracking experiments over the internet. We assessed the performance of two webcam-based eye-tracking techniques for behavioral research: manual annotation of webcam videos (manual eye-tracking) and the
automated WebGazer eye-tracking algorithm. We compared these methods to a traditional
infrared eye-tracker and assessed their performance in both lab and web-based settings. In
both lab and web experiments, participants completed the same battery of five tasks, selected
to trigger effects of various sizes: two visual fixation tasks and three visual world tasks testing
real-time (psycholinguistic) processing effects. In the lab experiment, we simultaneously collected infrared eye-tracking, manual eye-tracking, and WebGazer data; in the web experiment, we simultaneously collected manual eye-tracking and WebGazer data. We found that the two webcam-based methods are suited to capture different types of eye-movement patterns. Manual eye-tracking, similar to infrared eye-tracking, detected both large and small effects. WebGazer, however, showed less accuracy in detecting short, subtle effects. There was no notable effect of setting for either method. We discuss the trade-offs researchers face when choosing eye-tracking methods and offer advice for conducting eye-tracking experiments over the internet.

Abstract

A doubly quantified sentence, such as All hikers climbed a hill, allows two interpretations: Did all hikers climb different hills, or did they climb the same hill? Previous work has shown that comprehenders construct disambiguated logical representations of these interpretations (Raffray & Pickering, 2010). We extended this line of research by investigating whether bilingual logical representations are shared between languages or separate per language. We conducted four sentence-picture matching experiments in which we primed interpretations of doubly quantified sentences in Dutch and French monolingual and bilingual language comprehension. These experiments showed that bilinguals have fully shared logical representations and that logical representations constructed in the L1 and the L2 are comparable. Moreover, a control experiment ruled out that the priming effects were driven by visual overlap between prime and target pictures. We discuss these findings in terms of a language-dependent account of logical representations, although these findings can also be reconciled with the idea that logical representations involve conceptual mental models of sentence meaning.