Berkeley Study Finds Macaque Brains Flicker Between Conscious and Unconscious Images 15 Times a Second

Key points

• Doris Tsao and Janis Hesse at UC Berkeley published a preprint on bioRxiv on October 17, 2026, detailing neural activity in macaques during visual perception experiments.
• The study used binocular flash suppression, where one face is shown to one eye and a second face to the other, causing the brain to prioritize the new image while suppressing the first.
• Neural recordings in the inferotemporal and prefrontal cortices showed activity switching between patterns for the conscious and unconscious faces 15 times per second.
• The preprint garnered over two million views and 11,000 likes on social media within ten days, prompting Tsao to describe the reaction as 'surreal'.
• The findings are preliminary, involving only two macaques and specific visual brain regions, and have not yet been peer-reviewed.

Background

This research builds on decades of neuroscience efforts to understand how brains generate subjective awareness. Previous studies had detected weak neural signals for unconscious stimuli, but this work highlights strong, rapid alternation. It follows earlier coverage of consciousness-related topics, such as the link between intense breathing and cerebral blood flow drops, and debates on AI consciousness. The study adds to the ongoing 'consciousness wars' in neuroscience, where researchers debate whether consciousness is a spatial or temporal phenomenon.

How outlets are covering it

Nature emphasizes the surprise factor of finding strong neural signals for unconscious content and the rapid switching frequency, noting that some scientists found the social media buzz overblown. ScienceAlert highlights the temporal dimension of brain activity, suggesting that the brain may be sorting through alternative visual information without altering behavior. UA.News focuses on the methodological details, confirming the binocular flash suppression technique and the limitations of the study, including the small sample size. Gazeta Express frames the finding as a challenge to the notion of living in the present, questioning whether our seamless experience of reality is supported by complex neural activity. John Sakon of UCLA noted that some findings were not totally unexpected, contrasting with the enthusiasm of others.

Why it matters

This study offers a potential mechanism for how the brain manages competing visual inputs, which could help explain the subjective experience of consciousness. If the rapid switching of neural patterns is a key factor in consciousness, it could lead to new theories about how awareness is generated and how the brain prioritizes information. This could have implications for understanding disorders of consciousness and developing treatments for conditions where awareness is impaired.

What to watch

The study is currently a preprint and has not undergone peer review. Future research will likely involve larger sample sizes, more brain regions, and human subjects to validate the findings. Researchers will also investigate the mechanisms that orchestrate these transitions and why only some temporal segments become available to awareness. The social media attention may accelerate interest and funding for consciousness research, but peer review is essential to confirm the results.