Build Presence Before You Build Features
Zuckerberg has a specific definition of what makes VR worth building, and it has nothing to do with resolution or frame rate. The word he keeps returning to is presence, the feeling that you are actually somewhere and that someone else is actually there with you. He argues this is categorically different from every screen that came before. A phone or television can deliver high-fidelity content, but it cannot stop your brain from knowing you are looking at a rectangle on a wall. The surprising finding from Meta's early hand-tracking work illustrates how this thinking operates in practice. The assumption was that showing a full arm in VR would feel more realistic than showing hands alone. It turned out to be the opposite. When the elbow angle was even slightly off, users felt deeply uncomfortable. When the arms were removed entirely and only the hands were shown, users adapted immediately and felt fine. The lesson Zuckerberg draws from this is not about arms. It is about which psychological signals actually create or destroy the feeling of presence, and those signals are not always the obvious ones. He applies the same logic to eye contact. Video conferencing has reached a strange equilibrium where people stare at each other's faces for hours without ever making eye contact, because the camera is never where the eyes are. Zuckerberg describes this as a solved problem in VR, where even without precise eye tracking the system can infer gaze direction from head pose and create a reasonable approximation. With actual eye tracking, it becomes real. His point is that the features worth prioritizing are the ones that map to how the human brain actually reads other people, not the ones that look most impressive in a demo.