MIT neuroscientists discover the brain can reason without words | ScienceDaily

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MIT neuroscientists discover the brain can reason without words

Date:<br>August 11, 2026<br>Source:<br>Massachusetts Institute of Technology<br>Summary:<br>MIT neuroscientists have found striking evidence that language and logical reasoning are powered by separate systems in the brain. Even people with severe language impairments caused by stroke were able to solve challenging logic puzzles as well as people without those impairments, while brain scans showed that language-processing regions stayed largely quiet during reasoning tasks.<br>Share:

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A functional brain scan of a neurotypical participant in a new study shows a distinct separation between logic (green) and language (red/yellow) activations. Credit: Hope Kean, MIT

Talking through a difficult problem can help some people organize their thoughts. But according to cognitive neuroscientists at MIT's McGovern Institute for Brain Research, language itself is not required for logical reasoning.

In research published recently in the journal PNAS, a team led by MIT associate professor of brain and cognitive sciences Evelina Fedorenko found that people can successfully solve problems requiring logical reasoning even when their language abilities are severely impaired. Brain imaging also indicated that regions responsible for processing language are not recruited for logical reasoning.

Are Language and Thought Really Connected?

For thousands of years, philosophers, linguists, and cognitive scientists have debated whether language is essential for thought. Many have argued that people rely on language as a tool for thinking.

Hope Kean, a postdoc and former K. Lisa Yang Integrative Computational Neuroscience (ICoN) Center graduate fellow in Fedorenko's lab, says there are understandable reasons to think language and logic might be closely connected.

"Abstract thinking has properties that look a lot like language," Kean says, pointing to structural similarities. "You can decompose a thought into subcomponents, like little atoms of logical propositions, and you can combine them in a hierarchical manner to make more complex structured rules, very akin to language."

Still, Kean and Fedorenko, who is also a McGovern Institute investigator, suspected that the brain might separate the communication of reasoning from reasoning itself. People rely heavily on language when presenting a problem, discussing possible solutions, or explaining how they reached a conclusion. The underlying process of logical thought, however, might depend on a different brain system.

"There are aspects of thinking that seem to go beyond some of the limitations of language," Kean explains. Logical reasoning often requires a level of precision that ordinary language does not provide. Language also unfolds in a linear sequence, one word after another, while reaching a logical conclusion may require considering several pieces of information in ways that are less linear.

Testing Logical Reasoning Without Language

These questions led Kean to investigate how the brain actually performs logical reasoning. Studying the issue is challenging because researchers working with human participants normally rely on language to explain tasks and receive answers.

Fedorenko's group found a way around that obstacle by working with Rosemary Varley, a neuroscientist at University College London who studies acquired language disorders, and her team.

The researchers studied two people who had experienced strokes that damaged language-processing areas of the brain. Both had severe difficulty understanding and producing language.

To test reasoning without depending on language, the researchers developed logic games centered on numbers and visual patterns. In one task, participants saw two lists of numbers and had to determine the hidden rule that transformed one list into the other. A rule might involve reversing the digits or eliminating numbers above a certain value. After identifying the rule, participants had to use it on new examples.

Another task presented participants with a collection of geometric patterns. They then had to choose the pattern that correctly completed the matrix.

As the puzzles became more difficult, the results suggested that language was not necessary for this form of reasoning. The participants with severe language impairments performed as well as a control group. They could even convey the rules they had discovered through gestures or sketches.

"It really upends a theory that says that symbolic rule induction is not possible without linguistic capacities," says Kean.

Brain Scans Reveal a Divide Between Logic and Language

The researchers also examined what happens inside the brains of healthy adults while they solve logical problems.

Participants visited MIT for a series of MRI scans that recorded patterns of...