Abstract:

Humans are social animals. The representation and integration of social concepts is the basis of social semantic comprehension and social thinking. In recent years, it becomes a new research hotspot, bridging the gap between the neuroscience of language comprehension and social cognition. This article provides a review of current research on the processing of social concepts, focusing on three aspects: the definition of social concepts, the neural basis of social concept representation, and the neural basis of social concept integration.

The definition and scope of social concepts have undergone dynamic changes in research. Early studies mainly focused on specific social conceptual categories such as personality and mental states. In recent years, researchers have predominantly approached the definition of social concepts through the lens of semantic dimensions, placing emphasis on the degree to which these concepts encompass interpersonal interactions. By using the dimension-based definition of social concepts, these studies have broadened the scope of inquiry to encompass more generalized conceptual categories, including objects and actions.

The studies investigating the neural underpinnings of social concept representation have predominantly centered around two fundamental research inquiries. The first inquiry pertains to identifying the brain regions and networks that are implicated in the representation of social concepts, while the second inquiry seeks to determine whether the neural basis of social concepts is distinct from that of other types of concepts. Functional neuroimaging and lesion studies have consistently suggested that the representation of social concepts relies on a brain network composed of the bilateral anterior temporal lobes, temporo-parietal junction, dorsomedial prefrontal cortex, posterior cingulate cortex, and adjacent precuneus. This network exhibits the following characteristics: first, both activation levels and multi-voxel activation patterns of the brain regions in this network can reflect the distinction between social and non-social concept processing; second, most regions within the network exhibit specificity to social concepts, with only a few areas also sensitive to other types of concepts; thirdly, there are strong functional connections between brain regions within the network; fourthly, damage to specific brain regions within the network can impair social concept processing.

Regarding the neural foundations of social concept integration, the available evidence remains relatively sparse at present. Current studies of social concept integration typically adopt the paradigms that have been used to investigate general concept integration, and manipulate the sociality of experimental stimuli to examine the similarities and differences in neural correlates between social and non-social concept integration. The findings of these studies have provided preliminary indications that social and non-social concept integration have distinct neural correlates, and all of the major brain areas involved in social concept representation participate in one or more levels of social concept integration: phrase-level social concept integration may involve the anterior temporal lobes, discourse-level social concept integration mainly involves the temporo-parietal junction, and sentence-level social concept integration may engage all brain regions of the social-concept representation network. Additionally, the bilateral inferior occipital gyrus and temporal fusiform gyrus were found to be involved in phrase-level social concept integration, and the bilateral middle temporal gyrus were found to play a role in discourse-level social concept integration.

The research in the realm of social concept representation and integration is still in its nascent stages, with numerous aspects yet to be thoroughly explored and examined. The authors have put forth five notable topics that deserve special attention and investigation. These topics include exploring the underlying sub-dimensions of social concept representation, unraveling the intricate sub-components involved in social concept processing, delving into the functional specializations within the brain network that forms the foundation of social concept processing, clarifying the potential confound between social-semantic processing and general semantic and/or linguistic processing in the field of language comprehension, as well as comprehensively understanding the behavioral influences exerted by social concept processing.

Key words: concept representation, semantic integration, language comprehension, social cognition