People believe that their inner thoughts and feelings are much richer than what they are able to express in real time. Elon Musk has spoken publicly about this “bandwidth problem” as he has he described To podcaster Joe Rogan. This worries Musk so much, in fact, that he has made it one of his long-term goals to create an interface that would allow the human brain to communicate directly with a computer, without being tied to the slow speed of speaking or typing.
If Musk were to succeed, he would probably be disappointed. according to new research published in the neuronhumans think steady and slow speed about 10 bits per second—they remember, make decisions, and imagine things at that rate. In contrast, human sensory systems collect data at about a billion bits per second. This biological paradox highlighted in the new paper likely contributes to the false sense that our minds can engage in seemingly infinite thoughts, a phenomenon the study authors call the “Musk illusion.”
“The human brain is much less impressive than we thought,” says Markus Meister, a neuroscientist at the California Institute of Technology and study author. “It’s incredibly slow when it comes to making decisions, and it’s incredibly slow than any of the devices we interact with.”
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Meister and co-author Jieyu Zheng, a PhD student in neurobiology at Caltech, also point out in their paper that our brains can only do one thing—slowly—at a time. So even if Musk managed to connect his brain to a computer, Meister says, he wouldn’t be able to communicate with it any faster than if he were using a phone.
The new research builds on decades of psychology research showing that humans selectively perceive only a small portion of the information from their sensory experience. “We can only pay attention to so much, and that’s our conscious experience and what goes into memory,” says Meister. What has been missing from past research, he continues, is “any sense of numbers.” He and Zheng conducted their new review paper to try to fill this quantitative gap.
Meister and Zheng collected research data from a variety of fields, including psychology, neuroscience, technology, and human performance. They used a variety of these data—from the processing speed of single neurons to the cognitive skills of memory champions—to make their own calculations so they could make comparisons across studies.
From nearly a century of research, they found that human cognition has repeatedly been measured to operate at between 5 and 20 bits per second, with a figure of around 10 bits per second. “It was a very surprising number,” says Zheng. Based on that finding, he added, he and Meister calculated that the amount of information a person could learn in a lifetime could fit comfortably on a small disk.
Human sensory systems such as sight, smell, and sound, on the other hand, operate much faster, the authors found, 100,000,000 times the rate of cognition. “When you put these numbers together, you realize, oh my god, there’s this big gap,” Meister says. “From this paradox comes interesting new opportunities for science to organize research in a different way.”
The rich information conveyed by our senses also contributes to the false notion that we register extreme detail and contrast in our surroundings. But that’s “not true,” says Meister. When people are asked to describe what they see outside the center of their gaze, they “barely do anything,” he says. Because our eyes have the ability to focus on any detail around us, he continues, “our mind gives us the illusion that these things are present at the same time,” even though we actually need to focus on specific visual details to register them. . A similar phenomenon occurs with mental capacity. “In principle, we could have many different thoughts and focus our cognition in different ways, but in practice, we can only have one thought at a time,” says Meister.
Another problem with our overestimation of our own intelligence, he adds, is that we have no benchmarks. “There’s no way we can get it out of our heads to recognize that this isn’t really something to brag about,” he says.
The findings raise questions in a variety of domains, from evolution and technology to cross-species comparisons, the authors wrote. One of Meister and Zheng’s most curious questions, however, is why the prefrontal cortex—which is thought to be the seat of personality and behavioral control—has billions of neurons, but only 10 bits of information processing has a fixed decision-making capacity. per second The authors suspect that the answer may have something to do with the brain’s need to switch tasks frequently and integrate information across different circuits. But testing this hypothesis will require more complex behavioral studies.
Another important unanswered question, Meister says, is whether the human brain can do one thing at a time. “If we had 1,000 parallel thoughts, each at 10 bits per second, the discrepancy wouldn’t be as great,” he says. Why humans are unable to do this “is a deep mystery about which almost nothing is known.”
Tony Zador, a neuroscientist at Cold Spring Harbor Laboratory in New York state, who was not involved in the work but is cited in the paper’s acknowledgments section, says it’s “fantastic and thought-provoking” work that appears to be newly recognized as fundamental. true about the upper limit of the brain, “about the rate of typing or conversation.”
“Apparently, nature has built a speed limit into our conscious thoughts, and neural engineering will not be able to bypass it,” says Zador. “Why? We really don’t know, but it may be the result of our evolutionary history.’
Nicole Rust, a neuroscientist at the University of Pennsylvania who was not involved in the research, says the new research could reshape how neuroscientists approach some of their work.
“Why is it that our peripheral nervous system can process thousands of elements in parallel, but we can only do one thing at a time?” he says. “Any theory of the brain that wants to account for all the fascinating things we can do, like planning and problem solving, will have to take this paradox into account.”
