Neural signatures of response planning occur midway through an incoming question in conversation

Abstract

A striking puzzle about language use in everyday conversation is that turn-taking latencies are usually very short, whereas planning language production takes much longer. This implies overlap between language comprehension and production processes, but the nature and extent of such overlap has never been studied directly. Combining an interactive quiz paradigm with EEG measurements in an innovative way, we show that production planning processes start as soon as possible, that is, within half a second after the answer to a question can be retrieved (up to several seconds before the end of the question). Localization of ERP data shows early activation even of brain areas related to late stages of production planning (e.g., syllabification). Finally, oscillation results suggest an attention switch from comprehension to production around the same time frame. This perspective from interactive language use throws new light on the performance characteristics that language competence involves.

Planning versus comprehension in turn-taking: Fast responders show reduced anticipatory processing of the question

“…To address aim (1), the questions were designed such that response planning could start either early or late in the turn. Our results largely replicate Bögels et al (2015a), showing a large positive ERP effect and an oscillatory alpha/beta reduction right after participants could have first started planning their verbal response, again suggesting an early start of response planning. To address aim (2), the confederate's questions also contained either an expected word or an unexpected one to elicit a differential N400 effect, either before or after the start of response planning.…”

“…Indeed, an earlier EEG study suggests that listeners start planning their responses to questions as soon as they can (Bögels et al, 2015a). The present study aimed to (1) replicate this early planning effect and (2) investigate whether such early response planning incurs a cost on participants' concurrent comprehension of the ongoing turn.…”

“…In a recent EEG study, two novel neural correlates of speech planning suggested that listeners start planning their own turn as soon as they have enough information to do so (Bögels et al, 2015a). The timing of these neural correlates indicates that there is more overlap between comprehension and production than would be expected if listeners postponed response planning for as long as possible.…”

“…We hypothesize that such extensive dual-tasking-in the form of simultaneous comprehension and production planning-might come at a cost. The present study's aim is two-fold: (1) to replicate the presence and timing of neural correlates for response planning found in Bögels et al (2015a) study, and (2) to investigate whether comprehension of the incoming turn suffers during simultaneous production planning of an upcoming turn.…”

“…Another recent study used an interactive EEG paradigm to look into the processes of production planning during listening while participants were engaged in turn-taking (Bögels et al, 2015a). Using EEG precluded the need for an additional task (e.g., finger tapping or mouse tracking).…”