The Heidelberg researchers have hereby called into question the assumption to date that mental speed starts to decline already in early adulthood.
“The common assumption is that the older we get, the more slowly we react to external stimuli. If that were so, mental speed would be fastest at the age of about twenty and would then decline with increasing age,” says Dr von Krause, a researcher in the Quantitative Research Methods department headed by Prof. Dr. Andreas Vo at Heidelberg University’s Institute of Psychology.
To verify this theory, the researchers reevaluated data from a large-scale American study on implicit biases.The results were published in the journal Nature Human Behaviour.
In the online experiment with over a million participants, subjects had to press a button to sort pictures of people into the categories “white” or “black” and words into the categories “good” or “bad”.
According to Dr von Krause, the content focus was of minor importance in the Heidelberg study. Instead, the researchers used the large batch of data as an example of a response-time task to measure the duration of cognitive decisions.
On average, the response times of the test subjects rose with increasing age. However, with the aid of a mathematical model, they were able to show that this phenomenon was not due to changes in mental speed.
At the same time, motor execution speed slows down during adult life: older participants in the experiment needed longer to press the appropriate key after they had found the right answer.
Another finding of the study was that average information processing speed only progressively declined with participants over the age of 60.
Generally speaking, we should also note that the test subjects in all age groups included individuals with high and low mental speeds. Our results relate to the average trend.d