Your Brain May Be Switching Between Two Realities 15 Times Per Second, Study Suggests

The human brain might be switching between two versions of reality up to 15 times every second, according to a new study.

This rapid oscillation occurs as the brain processes visual information, deciding which aspects of our surroundings to prioritize for conscious awareness and which to largely ignore. While the brain is bombarded with more data than it can consciously process, a portion of this information is not entirely disregarded but rather flickers in and out of conscious perception.

Scientists have long sought to understand how the brain selects which sensory input reaches conscious awareness. Previous research often focused on the brain structures active during conscious perception. However, this latest study, led by researchers at the University of California, Berkeley, explored temporal patterns in this process.

Binocular Flash Suppression Experiment

To investigate this phenomenon, the researchers utilized an established technique called 'binocular flash suppression.' This method involves presenting different images to each eye simultaneously, often using specialized glasses. In the study's setup, one eye might be shown an image of a face, and then a second, different face is presented to the other eye while the first image remains visible.

Instead of perceiving both images at once, the brain typically prioritizes the newer stimulus, suppressing the older one from conscious awareness. However, by monitoring brain activity, the researchers observed a more dynamic process.

Neural Activity Patterns

In experiments conducted on macaque monkeys, tiny electrodes were placed within areas of the brain specialized for visual processing, particularly face recognition. The researchers recorded the electrical activity of hundreds of brain cells as the monkeys participated in the binocular flash suppression test.

They identified two distinct patterns of neural activity, each corresponding to one of the competing faces. Surprisingly, even when one face was consciously dominant, the brain's neurons did not exclusively represent that image. Instead, the recorded activity showed a rapid switching back and forth between the patterns associated with both faces, occurring approximately 15 times per second.

Unanswered Questions

This finding suggests that while one visual input may dominate conscious experience, the brain maintains representations of suppressed information, cycling between them at a high frequency. The study's preliminary findings, published in a pre-print paper on bioRxiv, indicate that neurons corresponded more sharply to features of the perceived face during moments of conscious awareness, hinting at a potential mechanism for distinguishing between the two streams of information. However, the precise mechanisms governing these transitions and determining what ultimately enters conscious awareness remain an open question in neuroscience.