This Is the Age When Your Brain Is at Its Most Random

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As a millennial and a writer, I’ve lived out my entire adolescence and young adulthood online, in the company of strangers. When I was a teenager, I had a Xanga account, then a Myspace, and even a LiveJournal for a period of time, filled with Bollywood lyrics and musings on how Tom Hanks was (and is) the perfect man. Now those have all been replaced by Twitter, Facebook, Instagram, and so many other venues where I can tap out whatever’s in my brain and send it off into the abyss.

These days, I try to keep my online presence more professional, using Twitter mostly to seek out sources and retweet Anderson Cooper. But if you scroll back through years’ worth of material on my social-media accounts, you’ll find posts that are completely all over the map. I’ve used Facebook to exalt Hanson’s Snowed In album, to rave about the Duggar family’s tater-tot-casserole recipe (it’s delicious, fight me), and to recap episodes of Dance Moms. My Twitter is even worse, hosting gems like Do you ever just Google different kinds of cakes and daydream about eating them? and Idris Elba could run my dog over with his car and I’d still love him.

A few days ago, I came across a study about randomness that’ll likely ring true for anyone else who’s starting to regret the stuff they spewed on Twitter in their early 20s. In research published last month in the journal PLOS Computational Biology, mathematician Nicholas Gauvrit and his team at the LABORES Scientific Research Lab, a research institution in Paris, discovered that when it comes to random thinking and decision-making, a person’s ability peaks at about age 25 and then gradually declines for the next several decades, eventually dropping off sharply at around age 60.

Gauvrit’s team came to its conclusion after assessing nearly 4,000 people between the ages of 4 and 91. Participants were instructed to predict the outcomes of certain tasks — like flipping a coin or rolling a die —so that the results would appear randomized. The study authors observed that the older a person got, the more difficult it was for them to mimic a random process; instead, their guesses would start to resemble a pattern rather than a series of all-over-the-map guesses. On average, the 25-year-old participants were the most adept at giving “random” answers.

Interesting, but it also raises the question: Why is studying “randomness” even important? Gauvrit and his colleagues argued that the ability to mimic a random process is a mentally difficult task, requiring sustained and focused attention, among other highly complex cognitive skills. In other words, if your answers are truly random, you’re at the top of your game, cognitively speaking.

Which, in turn, means that a person’s ability to generate randomness can be used to help determine a baseline of cognitive function. Past studies have shown that people with underlying neurological conditions, or those suffering from sleep deprivation, have a harder time with random simulations. In fact, scientists have been able to use randomized tasks like the ones in the PLOS study to examine the effect of diseases like Parkinson’s and schizophrenia on brain function.

Other studies show that success on these sorts of tests is also associated with creativity. Some researchers have argued that randomness is what allows human beings to brainstorm and solve problems. And humans aren’t the only ones who do it — in one 2014 study, for example, rats that were trying to outsmart a computer algorithm reverted to random behavior when all other options failed. Sometimes animals and humans need that spark of original thinking, and according to Gauvrit’s research, age 25 is when it’s most likely to happen.

My “random” behavior on social media probably wasn’t what Gauvrit and his team had in mind when linking randomness to creativity and cognitive function. But much like the rats in that earlier study, I’ve found random thinking to be an excellent last resort — I’ve been able to come up with an idea for an essay or an article during a spell of writer’s block simply by throwing random, unrelated thoughts on the page and seeing where they take me. Musing about Tom Hanks and different types of cake may not give me the most professional online presence, but if it gets the creative juices flowing, I’ll take it.

This Is the Age When Your Brain Is at Its Most Random