Until that brain pullup bar arrives from Amazon, this is probably your best bet.

When it comes to keeping your brain in tip-top shape, there’s clear evidence about what exercises are best to avoid. (For kids, this form of activity is proven to boost cognitive function.) But when it comes to finding the right non-bogus mental exercise, where is the best place to turn?

According to research published in the Journal of Cognitive Enhancement, your best bet is a memory sequence game called “dual-n-back.” The object of the game is to remember a constantly updating sequence of visual and auditory stimuli. In this case, participants saw a square appear on a screen while also hearing a letter. They were then tested on whether what they saw and heard was the same as the previous round. The game got progressively harder, asking participants to remember what they saw and heard two, three, and four rounds back, in addition to the sequence they just encountered.

This cranial workout hones in on your working memory, one of the five types of memory you have. Working, or short-term, memory is the segment of your brain that deals with remembering things like street addresses or directions and adapting responses to situations. 

“People say cognitive training either works or doesn’t work. We showed that it matters what kind of training you’re doing,” lead author Kara Blacke said in a press release. “This one task seems to show the most consistent results and the most impact on performance and should be the one we focus on if we’re interested in improving cognition through training.”

The study was conducted by Johns Hopkins University and involved three groups of young adult participants. They were first subjected to a baseline cognitive test to use as a point of reference for fluctuations in working memory, intelligence, and attention. They then underwent an electroencephalogram (EEG) to log brain activity. One group was used as a control, while the other two were tasked with a brain exercise to practice for 30 minutes, five days a week.

The group that was given a brain exercise called “complex span” saw a working memory improvement of around 15 percent; this game also involved remembering items in a sequence, but participants didn’t need to remember items from past rounds. However, the group given the “dual-n-back” exercise saw double the improvement, around 30 percent.

“The findings suggest that this particular task is changing something about the brain,” co-author Susan Courtney said in a press release. “There’s something about sequencing and updating that really taps into the things that only the pre-frontal cortex can do, the real-world problem-solving tasks.”