Scientists at the California Institute of Technology have uncovered a surprising truth about the speed of human thought: our brains process ideas at a rate of just 10 bits per second. Compared to the billion bits per second our sensory systems gather from the world around us, this is astonishingly slow.
Led by Markus Meister and graduate student Jieyu Zheng, researchers used information theory to analyze behaviors such as reading, writing, and solving puzzles. Despite having over 85 billion neurons, the brain’s overall thought process seems to remain constrained by its architecture.
The findings, published in the journal Neuron, revealed that the speed of human thought is far slower than technologies like Wi-Fi, which processes around 50 million bits per second. This disparity raises important questions about how the brain filters vast amounts of sensory input to focus on what truly matters.
Of course, a significant portion of these neurons is dedicated to the cortex, which is responsible for high-level thinking. While individual neurons can transmit more than 10 bits per second, interestingly, our collective thought process functions at a glacial pace.
This highlights a peculiar aspect of human cognition: we can process only one thought at a time, unlike our sensory systems, which operate in parallel. The researchers suggest that this limited speed of human thought may have evolutionary roots.
Early creatures with nervous systems used their brains primarily for navigation—finding food and avoiding predators. Over time, as brains evolved, this “one-path-at-a-time” mechanism likely carried over into more complex cognitive functions. The researchers say to think of human thought as navigating a space of abstract concepts, much like plotting a path on a mental map.
This discovery also has implications for futuristic technologies, such as brain-computer interfaces. While these devices promise faster communication, the inherent slowness of our cognitive processes may act as a bottleneck. Unfortunately, only time will tell.
However, there’s a silver lining here. Our ancestors thrived in environments where slow and deliberate thinking ensured survival. Perhaps the same can be said for us in a world where we aren’t always fighting for our lives against predators that want to kill us.
