In a groundbreaking study led by Professor Lin Nan at the Institute of Psychology of the Chinese Academy of Sciences, a remarkable discovery has challenged the traditional boundaries between language and social cognition in the human brain.
The research, published in Nature Human Behaviour, has revealed that the neural activity in two critical language regions of the brain, namely the left ventral temporoparietal junction (vTPJ) and the lateral anterior temporal lobe (lATL), is more closely linked to social-semantic working memory than to pure language processing.
Traditionally, language and social cognition have been treated as distinct domains of study. However, both sentence processing and social tasks have been known to activate the left vTPJ and lATL, suggesting a potential connection between language comprehension and social cognition.
Previous research attributed the activity in these brain regions during language tasks to general semantic and syntactic processing, while their involvement in social tasks was associated with the activation of social concepts. This led to the belief that these regions were primarily dedicated to language and social processing separately.
Professor Lin and the research team introduced a novel hypothesis challenging this separation. They proposed that the left vTPJ and lATL are active in both language and social tasks due to a shared cognitive component known as social-semantic working memory.
To test this hypothesis, the researchers conducted fMRI experiments. Their results confirmed that these brain regions were sensitive to sentences only when those sentences conveyed social meaning. Intriguingly, the left vTPJ and lATL exhibited sustained social-semantic-selective activity even after the linguistic stimuli had disappeared.
This finding suggested that these regions were engaged in processing the social aspects of non-linguistic stimuli as well. Additionally, the connectivity of these regions was found to be stronger with areas associated with social-semantic processing than with traditional sentence-processing regions. These groundbreaking findings challenge the conventional view that the left vTPJ and lATL are exclusively dedicated to language processing.
Instead, they emphasize the crucial role of these regions in language comprehension through social-semantic working memory. Professor Lin, the corresponding author of the study, noted the surprising nature of these results, considering the long-standing belief that the left vTPJ and lATL were primarily sensitive to sentence processing since the 1990s. The implications of this research are profound and multifaceted.
It calls for a significant re-evaluation of the functional organization of the cortical language network, suggesting a more integrated role for these regions in language and social cognition. Furthermore, the study contributes significantly to the field of social neuroscience, offering new insights into the neural underpinnings of language and social interaction. This groundbreaking research paves the way for a deeper understanding of the complex relationship between language and social cognition in the human brain.