Language is primarily for communication, not thinking

Fedorenko, E., Piantadosi, S.T. & Gibson, E.A.F. Language is primarily a tool for communication rather than thought. Nature 630, 575–586 (2024). https://doi.org/10.1038/s41586-024-07522-w

Abstract: Language is a defining characteristic of our species, but the function, or functions, that it serves has been debated for centuries. Here we bring recent evidence from neuroscience and allied disciplines to argue that in modern humans, language is a tool for communication, contrary to a prominent view that we use language for thinking. We begin by introducing the brain network that supports linguistic ability in humans. We then review evidence for a double dissociation between language and thought, and discuss several properties of language that suggest that it is optimized for communication. We conclude that although the emergence of language has unquestionably transformed human culture, language does not appear to be a prerequisite for complex thought, including symbolic thought. Instead, language is a powerful tool for the transmission of cultural knowledge; it plausibly co-evolved with our thinking and reasoning capacities, and only reflects, rather than gives rise to, the signature sophistication of human cognition.

Carl Zimmer has an article about this in the NYTimes. After giving some background, specifically noting we have a language network in the brain that's distinct from other networks:

The researchers then scanned the same people as they performed different kinds of thinking, such as solving a puzzle. “Other regions in the brain are working really hard when you’re doing all these forms of thinking,” she said. But the language networks stayed quiet. “It became clear that none of those things seem to engage language circuits,” she said.

In a paper published Wednesday in Nature, Dr. Fedorenko and her colleagues argued that studies of people with brain injuries point to the same conclusion.

Strokes and other forms of brain damage can wipe out the language network, leaving people struggling to process words and grammar, a condition known as aphasia. But scientists have discovered that people can still do algebra and play chess even with aphasia. In experiments, people with aphasia can look at two numbers — 123 and 321, say — and recognize that, by using the same pattern, 456 should be followed by 654.

If language is not essential for thought, then what is language for? Communication, Dr. Fedorenko and her colleagues argue. Dr. Chomsky and other researchers have rejected that idea, pointing out the ambiguity of words and the difficulty of expressing our intuitions out loud. “The system is not well designed in many functional respects,” Dr. Chomsky once said.

Zimmer's article links to a number of other studies.