Psychological research has advanced considerably with the advent of noninvasive brain imaging techniques, which have been further enhanced by recent developments in neuroscientific analysis methods. These advancements have enabled scientists to assess similarities and dissimilarities in neural activity between individuals, thereby establishing neuroscientific approaches as powerful tools for elucidating the characteristics of dyadic and group relationships. In this paper, we introduce the features of cutting-edge neuroimaging analysis techniques and explore the emerging relationship between shared reality and social connections. We specifically argue from the perspective of neural homophily that similarity in how individuals perceive the world is crucial for the formation and maintenance of social connections. Furthermore, we offer a novel perspective on the mechanisms by which individuals may become socially isolated and experience loneliness, suggesting that these processes are driven by a lack of shared reality. Finally, we outline future directions, highlighting new questions expected to be addressed through technological advancements, and propose pathways to deepen our understanding of social connections.
