Encouraging prediction during production facilitates subsequent comprehension: Evidence from interleaved object naming in sentence context and sentence reading

Beyond speaking: neurocognitive perspectives on language production in social interaction

The human faculty to speak has evolved, so has been argued, for communicating with others and for engaging in social interactions. Hence the human cognitive system should be equipped to address the demands that social interaction places on the language production system. These demands include the need to coordinate speaking with listening, the need to integrate own (verbal) actions with the interlocutor's actions, and the need to adapt language flexibly to the interlocutor and the social context. In order to meet these demands, core processes of language production are supported by cognitive processes that enable interpersonal coordination and social cognition. To fully understand the cognitive architecture and its neural implementation enabling humans to speak in social interaction, our understanding of how humans produce language needs to be connected to our understanding of how humans gain insights into other people's mental states and coordinate in social interaction. This article reviews theories and neurocognitive experiments that make this connection and can contribute to advancing our understanding of speaking in social interaction. This article is part of a discussion meeting issue 'Face2face: advancing the science of social interaction'.

The role of language production in making predictions during comprehension

Language comprehension depends heavily upon prediction, but how predictions are generated remains poorly understood. Several recent theories propose that these predictions are in fact generated by the language production system. Here, we directly test this claim. Participants read sentence contexts that either were or were not highly predictive of a final word, and we measured how quickly participants recognised that final word (Experiment 1), named that final word (Experiment 2), or used that word to name a picture (Experiment 3). We manipulated engagement of the production system by asking participants to read the sentence contexts either aloud or silently. Across the experiments, participants responded more quickly following highly predictive contexts. Importantly, the effect of contextual predictability was greater when participants had read the sentence contexts aloud rather than silently, a finding that was significant in Experiment 3, marginally significant in Experiment 2, and again significant in combined analyses of Experiments 1-3. These results indicate that language production (as used in reading aloud) can be used to facilitate prediction. We consider whether prediction benefits from production only in particular contexts and discuss the theoretical implications of our evidence.

Cognitive control ability mediates prediction costs in monolinguals and bilinguals

In this study, we examined the role that cognitive control and language regulation ability play in mediating readers' susceptibility to prediction error costs when reading in the native language (L1) or a second language (L2). Twenty-four English monolinguals (Experiment 1) and 28 Chinese-English bilinguals (Experiment 2) read sentences in English while their EEG was recorded. The sentences varied in the predictability of an upcoming expected word and in whether that prediction was confirmed. Monolinguals showed sensitivity to sentence contexts in which expectations were not met (i.e., when unexpected words were encountered) in the form of a late, frontally-distributed positivity, but for bilinguals this effect was more complex. For both groups, performance on the prediction task was modulated by individual differences on the AX-CPT, a measure of inhibitory control. However, the bilinguals' reading performance in the L2 was affected not only by inhibitory control, but also by their performance on an L1 verbal fluency task that indexed language regulation and production capability, related to their language dominance and immersion context. Bilinguals with better regulation of the L1 generated a larger frontal positivity in response to unexpected words in the L2, an effect that was attenuated by inhibitory control ability. In contrast, bilinguals with lower regulatory ability generated a larger, late negativity, which was also mediated by control. These findings suggest that the ability to regulate the native language when immersed in a second language environment can influence mechanisms underlying the prediction process when reading in the L2. In addition, cognitive control ability, specifically inhibitory control, appears to mediate the difficulty readers incur when predictions are disconfirmed, not only in the native language, but also for proficient bilinguals reading in the L2. We argue that the mechanisms engaged during prediction in the L1 and L2 are fundamentally the same, and that what differs for bilinguals are the additional demands imposed by their language experience and language use.

Prediction is Production: The missing link between language production and comprehension

Language comprehension often involves the generation of predictions. It has been hypothesized that such prediction-for-comprehension entails actual language production. Recent studies provided evidence that the production system is recruited during language comprehension, but the link between production and prediction during comprehension remains hypothetical. Here, we tested this hypothesis by comparing prediction during sentence comprehension (primary task) in participants having the production system either available or not (non-verbal versus verbal secondary task). In the primary task, sentences containing an expected or unexpected target noun-phrase were presented during electroencephalography recording. Prediction, measured as the magnitude of the N400 effect elicited by the article (expected versus unexpected), was hindered only when the production system was taxed during sentence context reading. The present study provides the first direct evidence that the availability of the speech production system is necessary for generating lexical prediction during sentence comprehension. Furthermore, these important results provide an explanation for the recruitment of language production during comprehension.