Poster C27, Wednesday, August 21, 2019, 10:45 am – 12:30 pm, Restaurant Hall
Shared situation models between production and comprehension: fMRI evidence on the neurocognitive processes underlying the construction and sharing of representations in discourse
Karin Heidlmayr1,2, Kirsten Weber1,2, Atsuko Takashima1,2, Peter Hagoort1,2;1Max Planck Institute for Psycholinguistics, 2Donders Institute for Brain, Cognition and Behaviour, Radboud University
To communicate a complex issue or situation, speakers and listeners usually exchange information in the form of larger discourse, such as narratives or expository texts. Importantly, to understand the meaning of a larger discourse, information needs to be integrated over an extended period of time to build a coherent situation model, i.e., a mental representation of the situation denoted in a text (Zwaan & Radvansky, 1998; Zwaan & Singer, 2003). To process a situation model, links between successive utterances within the text, but also with world-knowledge beyond the content of the discourse have to be made. It is not yet clear to which degree the different neurocognitive processes are shared between the speaker and the listener to assure the listener’s comprehension of the situation model, in other words the parity of representations between production and comprehension (Pickering & Garrod, 2004, 2006). The goal of the present study was to identify the neural bases reflecting how situation models are constructed and shared between speakers and listeners. We designed an fMRI pseudo-hyperscanning study using a variant of the ambiguous text paradigm (Dooling & Lachman, 1971; Bransford & Johnson, 1972), i.e., conceptually ambiguous expository texts were presented with preceding contextual information that in some cases did and in others did not facilitate the extraction of a coherent situation model. Fifteen speakers produced ambiguous texts preceded by a highly informative title in the scanner and 27 listeners subsequently listened to these texts, preceded by either a highly informative, intermediately informative (highly/intermediately informative title condition) or no title at all (absent title condition). The interlocutors’ brain activity related to situation model processing was expected to vary with comprehension-relevant contextual information, even though linguistic and sensory information was equal across conditions. Conventional BOLD activation analyses in listeners, as well as inter-subject correlation (ISC) analyses (Hasson et al., 2004) between the speakers’ and the listeners’ hemodynamic time courses were carried out. Independent of the information provided by the title, discourse processing was associated with activation in the left-dominant fronto-temporal language network (Hagoort, 2017). However, only the processing of coherent discourse involved (shared) activation in bilateral lateral parietal and in medial prefrontal (mPFC) regions. More specifically, in listeners, the bilateral lateral parietal cortex (supramarginal gyrus, angular gyrus) showed higher BOLD activation in the highly informative than the intermediately informative and absent title conditions. Moreover, the listeners’ rating of text comprehension was positively correlated with speaker-listener ISC in the mPFC. Hence, the constitution of large-scale conceptual representations, i.e., situation models, and their sharing between interlocutors seems to draw on activation in high-level convergence zones in the lateral parietal cortex and on inferencing and episodic memory retrieval in the medial prefrontal regions. This shared pattern of brain activation between the speaker and the listener suggests that the process of memory retrieval and the binding of retrieved information in overlapping areas between speakers and listeners enables the communication of complex conceptual representations.
Themes: Meaning: Discourse and Pragmatics, Methods
Method: Functional Imaging