
Assumptions that a person’s mental speed peaks at 20 years of age may have been debunked by a new study examining the reaction times of more than 1 million people.
By analysing data from 1.2 million subjects who participated in an online experiment, international researchers have determined that the mental processes people use to decide on a correct answer do not start to slow until 60 years of age.
The researchers used what is known as a ‘Bayesian diffusion model’ to extract interpretable cognitive components from raw response time data of a task that asked participants to make a selection of words and images that flashed up on a screen by pushing the correct key in response.
The paper, published in Nature Human Behaviour last week, explained although recorded response times did slow for participants after age 20, this was likely attributed to more caution towards decision-making a subject exercised the older they were.
“Response speeds in simple decision-making tasks begin to decline from early and middle adulthood (as early as age 20). However, response times are not pure measures of mental speed but instead represent the sum of multiple processes,” the paper said.
The team also noted other factors (referred to as non-decisional processes) which may also have slowed older subjects’ reaction times to the cognitive task, including being less tech-savvy and therefore taking longer to identify which button to press on the computer.
Good news everyone – according to our new preprint, cognitive speed stays high throughout young and middle adulthood @MLSicorello @AnnaLSchubert @JeffRouder https://t.co/tGu9c4U5JR #BigData #BayesFlow
— Mischa von Krause (@mischavk) March 18, 2021
The study shows how for much of our lives, and during the timespan of a typical career, age-related slowdowns in mental speed are not likely to be the reason for a slower response among older people. The findings challenged previous assumptions that mental speed peaked at age 20, and also confirmed that reaction time progressively declines from age 60 onwards.
The research was supported by a grant from the German Research Foundation to the graduate school 530 SMiP.
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