24 is the new 40.
That's according to researchers at Canada's Simon Fraser University, who have found that measurable declines in cognitive performance begin to occur at age 24. In terms of brainpower, you're over the hill by your mid-20s.
The researchers measured this by studying the performance of thousands of players of Starcraft 2, a strategy video game. If tennis is a hybrid of boxing and chess, as David Foster Wallace held, then Starcraft is a hybrid of boxing, chess, Risk, Monopoly, and Candy Crush. The game is incredibly fast-paced and complicated. The goal is to harvest resources, build an army, and crush your opponent, who is trying to do the same.
Like economists, Starcraft players think in macro and micro terms - they must focus on the long-term goals of building a healthy economy that can sustain an army of hundreds of units, while simultaneously maneuvering and issuing commands to each of those units, often individually. Because everything happens in real time, the only limit on player performance is the speed at which they're able to zip around the playing field and perform actions via their keyboard and mouse. For a sense of what the game looks like from the player's viewpoint, check out the video below.
The game provides an excellent real-world laboratory for testing cognitive ability under pressure. It's already used in a University of Florida Honors class to teach "critical thinking, problem solving, resource management, and adaptive decision making." In studying game replays, the researchers at Simon Fraser found that "looking-doing latency" - the delay between when a player looked at a new section of the game field, and when they performed an in-game action - is lowest among 24-year-old players. After age 24, that lag only increases as you get older. The researchers calculate that over an average 15-minute game of Starcraft, a 39-year-old player loses 30 seconds to cognitive lag versus a 24-year-old. In a game where performance is measured in hundreds of actions per minute, this is a huge deficit.
Even worse news for those of us who are cognitively over-the-hill: the researchers find "no evidence that this decline can be attenuated by expertise." Yes, we get wiser as we get older. But wisdom doesn't substitute for speed. At best, older players can only hope to compensate “by employing simpler strategies and using the game’s interface more efficiently than younger players,” the authors say.
So there you have it: scientific evidence that we cognitively peak at age 24. At that point, you should probably abandon any pretense of optimism and accept that your life, henceforth, will be a steady descent into mediocrity, punctuated only by the bitter memories of the once seemingly-endless potential that you so foolishly squandered in your youth. Considering that the average American lives to be 80, you'll have well over 50 years to do so!
Your sole solace? At least you don't live in Russia.