Does learning languages slow brain aging?
A study's methods & muddy data are interesting—but not proof of causality.
What’s News? is a daily look at new aging & longevity science & ideas. Posts ≠ endorsements.
Summary: Researchers in Spain scanned the brains of 144 people in the Basque region, a place where speaking three or four languages is unremarkable. They fed the scans to an AI that was trained on the brains of 728 other people and asked the AI to guess how old each brain looked, based on how well its circuits were wired together. Bilinguals came out roughly 6 years younger than their actual age. Trilinguals, 7. People with four languages appeared to be 13 years younger.
This was a talk at a neuroscience conference, not a peer-reviewed paper. Research based on 144 people split four ways (ie, about 36 per group) is methodologically thin. The decreases in brain age are strange: one extra year for a third language…but six more for a fourth? Also, people who juggle four languages tend to be well-educated, well-traveled and socially busy. The researchers say languages "slow" brain aging—suggesting causation. But their data can't show that.
Context: The languages-aging argument has been running for two decades, and it’s been a very mixed scientific bag. Headlines often wrongly imply (or outright state) causality that the data don’t support—as the press release about this study and the Guardian’s write up about it each do. The language-aging investigations started in earnest in 2007, when a Toronto team looked at 184 dementia patients and found people who speak two languages showed symptoms about four years later than folks who speak only one. Other studies since have found delays in the range of ~4 to 5.5 years. But many others found no effect at all. A 2020 meta-analysis offered what amounts to a split verdict: bilingual people may develop dementia later but they're no less likely to develop it, and the studies feeding that conclusion were inconsistent enough to make the study authors regard them as biased.
Bottom line: A 13-year effect from an unpublished abstracted presented at a conference isn’t breaking new ground but, rather, adding another stratum to the argument over whether language-learning impacts longevity.
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