The brain remains sharp into middle age, contrary to popular assumptions that mental processing speed slows after the 20s and 30s. This is what research published in the journal Nature Human Behavior suggests. The study of 1.2 million people, ages 10 to 80, found that mental speed remained relatively stable between ages 30 and 60 — but caution in decision-making tends to increase with age.

Response speeds in simple decision-making tasks begin to decline from early and middle adulthood. However, response times are not pure measures of mental speed but instead represent the sum of multiple processes. 

Researchers at the University of Heidelberg in Germany used an online task to estimate people’s decision-making time. They showed participants a series of images online and asked them to put them into two categories — good or bad — by pressing different buttons to do so.

Slowing of mental speed was observed only after approximately age 60. The paper thus challenges widespread beliefs about the relationship between age and mental speed.

The study found that:

• People under 18 were less cautious and more willing to give up precision for speed;
• Caution in decisions increased between 18 and 65 years old;
• People also took longer to press the respective button the older they were.

“For much of typical human life and work careers, our results challenge the widespread notion of an age-related slowing of mental speed,” the study concludes.

Source: Nature | BBC