How many digits can you remember at once? Psychologists refer to this as a digit span test.
For example, I might give you a number like 59368572 and ask you to repeat it back to me. Typically, people can hold about seven digits in their head at once, give or take a few.
As it turns out, though, this ability can be trained. In the 70s and 80s, researchers at Carnegie Melon University trained Dario Donatelli, a runner on the school’s cross-country team, to remember 104 digits at once – even though he had started with the ability to remember only 8.
This led one of the researchers involved in the research to conclude that “To be an expert, you don’t have to be brilliant, you just have to work at it.”
There’s no doubt that Donatelli became one of the world’s foremost experts in remembering digits. Once the experiment wrapped up, though, Donatelli went on with his life. He became the coach of Carnegie Melon’s cross-country team, and presumably found other things to do besides sitting around remembering 104-digit numbers.
All of which is to say: he stopped using his spectacular memorization abilities.
So recently, a team of psychologists from Florida State University decided to follow up with an interesting question: after 30 years of disuse, what does Donatelli’s ability to remember numbers look like now?
In their study, the researchers tested Donatelli’s digit span over the course of three days.
On the first day of testing, Donatelli could remember only 10 digits at a time. Above average, no doubt, but far short of the 104-digit feats of his youth!
However, there was some evidence of Donatelli’s former powers. In only three days of testing, he increased his memory span to 19 digits.
Clearly, then, even exceptional abilities can be lost if they aren’t used – although, at least to some extent, they may come back more quickly with practice.
As one of the researchers from the original study said, if you want to be an expert, all you have to do is work at it. And thanks to this latest study, we can now say that if you don’t want to be an expert anymore, all you have to do is stop working at it.