The brain is sometimes called the most complex machine in the known universe. But the thoughts that it outputs putter along at a trifling 10 bits per second, the pace of a conversation
The findings raise questions in many domains, from evolution and technology to cross-species comparisons, the authors write. One of the questions Meister and Zheng are most curious about, though, is why the prefrontal cortex—thought to be the seat of personality and behavioral control—houses billions of neurons yet has a fixed decision making capability that processes information at just 10 bits per second. The researchers suspect the answer might have something to do with the brain’s need to frequently switch tasks and integrate information across different circuits. But more complex behavioral studies will be needed to test that hypothesis.
Another important unanswered question, Meister says, is why the human brain can do only one thing at a time. “If we could have 1,000 thoughts in parallel, each at 10 bits per second, the discrepancy wouldn’t be as big as it is,” he says. Why humans are incapable of such mental multitasking is “a deep mystery that almost nothing is known about.”
Anthony Zador, a neuroscientist at Cold Spring Harbor Laboratory in New York State, who was not involved in the new paper but is mentioned in its acknowledgments, says the “wonderful and thought-provoking” study presents what seems to be a newly recognized fundamental truth about the brain’s upper limit of “roughly the pace of casual typing or conversation.” {read}