Atypical functioning of cortico-striatal brain networks that support cross-modality—a key human cognitive ability—may underlie altered processing of the self in schizophrenia, autism spectrum disorders, and synesthesia. This disruption affects both the minimal self and the narrative self. The authors link these cognitive conditions to an atypical presentation of human self-domestication features, building on prior work connecting cognitive disorders and language evolution. This framework unifies linguistic and non-linguistic symptoms through deficits in the notion of self, supports the hypothesis that schizophrenia and autism are diametrically opposed conditions, and suggests that their origins are tied to recent human evolution, offering cues for earlier and more accurate diagnosis.
Human consciousness is often considered a form of inner speech, and humans possess exceptional narrative abilities that extend beyond language. This paper argues that evolutionary changes in the brain's narrative hardware, along with behavioral changes that culturally complexified language, improved the ability to tell stories to others and to oneself. This enhancement of inner storytelling may have sophisticated human consciousness. The authors suggest that improving generative story production could favor the emergence of consciousness in other entities, including artificial intelligence.