Science Digest: What Really Happens to Your Brain After 40

“Age and cognitive skills: Use it or lose it” paper was published March 2025 in Science Advances, a leading (Q1) peer-reviewed journal in neuroscience and economics. This paper challenges one of the most commonly accepted beliefs about aging: our mental sharpness inevitably declines starting in our thirties. Using rare longitudinal data, the authors ask whether this “decline” is biological fate or simply a matter of how much we keep using our brains.

The Study in a Nutshell

Researchers from Stanford University, the University of Munich, and DIW Berlin analyzed data from more than 3,000 German adults (both men and women) aged 16–65. They retested their literacy and numeracy skills over 3.5 years to see how individual abilities actually changed with age.

The team used data, which measures practical reading and math skills used in daily life and work. They also corrected for testing errors that can skew results and looked at how often people use these skills at work or home to see how that affects changes in thinking ability over time.

The study is unique since information was collected from the same individuals repeatedly over time (longitudinal data) rather than just comparing different age groups at one point (which is called cross-sectional data).