Abstract

There is a growing body of research demonstrating that during comprehension, language users predict upcoming information. Prediction has been argued to facilitate dialog in that listeners try to predict what the speaker will say next to be able to plan their own utterance early. Such behavior may enable smooth transitions between turns in conversation. In face-to-face dialog, speakers produce a multitude of visual signals, such as manual gestures, in addition to speech. Previous studies have shown that comprehenders integrate semantic information from speech and corresponding iconic gestures when these are presented simultaneously. However, in natural conversation, iconic gestures often temporally precede their corresponding speech units with substantial lags. Given the temporal lags in gesture-speech timing and the predictive nature of language comprehension, a recent theoretical framework proposed that listeners exploit iconic gestures in the service of predicting upcoming information. The proposed study aims to test this proposal. We will record electroencephalogram from 80 Dutch adults while they are watching videos of an actress producing discourses. The stimuli consist of an introductory and a target sentence; the latter contains a target noun. Depending on the preceding discourse, the target noun is either predictable or not. Each target noun is paired with an iconic gesture whose presentation in the video is timed such that the gesture stroke precedes the onset of the spoken target either by 520 ms (earlier condition) or by 130 ms (later condition). Analyses of event-related potentials preceding and following target onset will reveal whether and to what extent targets were pre-activated by iconic gestures. If the findings reveal support for the notion that iconic co-speech gestures contribute to predictive language comprehension, they lend support for the recent theoretical framework of face-to-face conversation and offer one possible explanation for the smooth transitions between turns in natural dialog.