The private mind is a historically recent construct tied to literacy

Evidence

The private experience of the infant may not lead in any continuous way to the private mind of the adult. Moreover, we might expect that the psychology of FP-P has undergone more dramatic changes over historical time than have other dimensions of folk psychology. For example, humans have moved from oral cultures of experience to the private consumption of experience in books. — Roderick M. Kramer, Geoffrey J. Leonardelli, Robert W. Livingston, Social Cognition, Social Identity, and…, 427

Categorization

• DEEPTHINKING: This inverse of the usual ToM framing — that the private, interior mind may be a cultural artifact of reading rather than a biological given — is a genuinely dizzying reframe of what we normally treat as bedrock.
• SHARE: Send to the friend who works on how literacy changes cognition; the claim that interiority itself scales with text consumption is exactly their wheelhouse.
• corroborated: 2 independent passages support this claim — Roderick M. Kramer, Geoffrey J. Leonardelli, Robert W. Livingston, Social Cognition, Social Identity, and…, 427