The processing speed of the human brain remains high until the age of 60, according to a new study that challenges previous assumptions that mental speed peaks at age 20.
As humans age, it takes longer for them to respond to changes in our environment or stimuli. Previous research has shown that this slowdown in response time begins from around age 20, gradually continuing to increase as people age.
In societies around the world, older people are often assumed to be slower thinkers than younger people, and this notion has important consequences in working life as well.
The new research, published in the journal Nature Human behavior Thursday tested this theory by analyzing more than a million participants from a wide age range who had taken part in an online experiment measuring their reaction times to a cognitive task.
Participants had to categorize a selection of words and images that appeared on a screen by pressing the correct key in response.
Although response times appear to slow after the age of 20, scientists from the University of Heidelberg in Germany said this could be due to increased decisional caution and slower non-decisional processes, such as as long as it takes to press the key.
The researchers said response times are not pure measures of mental speed, but rather represent the sum of multiple processes.
They used machine learning to extract more information and determine if someone was responding slowly to a question, whether it was due to slow motor responses or a slow cognitive response.
“Our results indicate that slowing in response time begins as early as age 20, but this slowing was attributable to increased decisional caution and slower non-decisional processes, rather than differences in mental speed. “, they wrote in the study.
“It is only after around 60 years that drift rates begin to show an acceleration of age-related negative decline, with the lowest mean values found for the oldest participants,” the scientists added. .
The results also suggest that college-aged people (18-20) were the least cautious because they “were the most willing to trade off accuracy for speed.”
According to the study, participants between the ages of 14 and 16 were the fastest in the mechanical part of the answer, quickly pressing the button on the keyboard after finding the answer to the test question.
“After age 18, decision conservatism increases linearly until about age 65 in the incongruent condition, with a larger increase each year thereafter until age 80,” the scientists noted.
Based on the research, the scientists said that despite widespread belief in age-related slowdowns in mental speed, for much of human life, and over the span of a typical career, this n is probably not the case.