Sometimes people complain when trying to learn a new skill: I'm not that young anymore. It’s harder to learn anything new. But adult brains may be more pliable than we thought. Research has shown that adult brains can increase in gray matter over weeks or months. Now comes a study finding that it’s possible to increase the brain’s gray matter quite quickly—in only a matter of days. That’s according to research in the Proceedings of the National Academy of Sciences. [Veronica Kwok et al., "Learning new color names produces rapid increase in gray matter in the intact adult human cortex"]

The scientists created an experiment that mimicked how young children learn new words. They took four similar shades of green and blue and gave them made-up names—meaningless Mandarin monosyllables like sòng. Nineteen adults learned to match those names and shades in five sessions over three days, a total of an hour and 48 minutes.

The scientists took MRI images of the subjects’ brains before and after the experiment. And they found a noticeable increase in gray matter volume in the regions known to be related to color vision and perception. The researchers contend that the adult brain is thus more changeable more quickly than anyone thought. And that an old dog can learn a new trick.