When we were kids, it seemed like we were always being told about the untapped potential of the brain. We dunderheads were only using a few percent of the computing power, while even the geniuses among us weren’t cracking a tenth of the brain’s capacity. The future was all promise, possibility. Surely we would keep growing smarter and smarter and smarter. It didn’t quite go to plan.

Even now, with research into artificial intelligence and microdosing on the rise, we are again entertaining fantasies of an unbound superbrain – robotic, psychedelic, or otherwise. Meanwhile, all the empirical evidence available to us seems to suggest quite the opposite is happening. Names have begun to escape us. Anecdotes, once so much a part of our dinner-party charm, elude us midway through their retelling. Phone numbers, historical facts, the purpose of our walking into this room... gone.

“The brain is functionally deteriorating and growing noisier in its operations, so it’s operating less precisely,” says Dr Mike Merzenich, a professor emeritus neuroscientist at the University of California, San Francisco, author of Soft-wired, and creator of BrainHQ, a gymnasium of sorts for maintaining neural function. “When you’re older, the brain is generally recording information with less clarity,” he says. “So it has to operate with slower cycle times in all of its operations. It samples more slowly, and takes longer to make all of its decisions. That’s why older people are not high performers in athletics or in their cognitive abilities.”

So, if we are not all going to be Einsteinian psychonauts in our dotage, is there anything we can do to fend off the encroaching noise and slippage of the brain’s capabilities? “We’re all works in progress,” Dr Merzenich says, “and everybody can be stronger and better. Everyone should be thinking about how they can adopt a life of continuous growth instead of sort of ongoing progressive retreat into the swamp, because we all have the potential basically to turn that around and we all have the potential to have a better older life.”

Here, we lay out a few of the best ways to maintain the brain clarity, plasticity and zip.

Practicing a meditation-level focus on our present is actually the best way to organise our creation of memories and the information gathered from stimuli and experience, says Dr Merzenich. “Our goal is to be connected with our physical environment very directly, really looking at what’s in front of you, really listening, really smelling the roses. That way, you’re actually connected with the physical reality of the world that you’re moving in, and that’s a critical thing. We’re not really designed to withdraw from the world, to be walking zombies. Certainly, in our native human state, we weren’t allowed to.” Now, though, at least we won’t be eaten for daydreaming.

The problem is: boredom, distraction, texting, Instagramming and checking the scores have come along and swept away anything like attentiveness to the physical world around us. The brain sags, and we slip from the child-like wonder and focus to which we were born. But, “you want to get back there,” Dr Merzenich councils. “You want to be like a child again.” So, if you want to stay alert, make an effort to be engage with and be aware of the world around you.

As adults, we’re not engaging our brain very much in continuous new learning, says Dr Merzenich. “We’ve learned our fundamental skills and abilities when we were young. And we’re now on automatic pilot, and that’s a really bad thing for the brain. The brain needs that machinery to be engaged. It dies off if you don’t use it.”

Especially now, in an age when we commodify all of our activities and tend to disengage from whatever we cannot monetize, some effort is required to pick up something just for ourselves, something just for fun. So, nurture curiosity, try things out, pick up hobbies. Learn new languages, take up ceramics. Because, in a state of continual learning, your brain will remain its freshest and most adaptable.

Socrates said the best intellectual challenge is to make new acquaintances – and who are we to argue? “It’s so important that we continually engage our brain on the social behavioral dimension of our life,” Dr Merzenich says, “continue to exercise your social, cognitive resources in the brain. Because they’re substantially separated in the brain from the more generally cognitive operations. Social cognition is in a sense its own special domain and it’s very strongly tied to aspects of emotion control.” And, as we are beginning to see, loneliness is a real threat. “It is very important that you also try to sustain a social life. That’s a real problem in many older people. There’s so many lonely people, people who have little human interaction and it’s so bad for them.”

Make a plan to meet some new friends, and see old friends again – those who will expand your frame of references, bring new inside jokes, new ideas, give you new venues for expression of yourself.

Treat your brain like a muscle. Work it out and massage it as if it were an athlete. And, like an athlete, train it specifically for the tasks in which you’d like it to be most competitive. For example, “Doing crossword and Sudoku puzzles seems to make you better at that activity, but the benefits don’t transfer to any broader abilities,” says Ms Angela Gutchess of Brandeis University, Massachusetts, and author of the forthcoming book, Cognitive And Social Neuroscience of Aging (Cambridge Press). “So if you enjoy those activities, continue with them. But if it’s not your thing, find something else that challenges you in an enjoyable way.”

“When you’re young, you’re agile and able to control your actions,” Dr Merzenich says. “Your physical actions have great facility at speed. Now, you’re older and you’re sluggish and you’re sloppy in your control. You want to try to maintain your accurate ability at speed, just like when you were younger. That is, making highly accurate decisions, translating visual information into action at high speed.”

Dr Merzenich suggests: “Riding your bike across the countryside is healthy in the same sense of making these fast, accurate distinctions about what you’re seeing in relation to the control of your actions. That’s a very valuable type of thing to do.”

There is little worse for the brain than idling. “In terms of factors linked to poorer brain ageing,” says Ms Gutchess, “a sedentary lifestyle – sitting on the couch watching lots of TV – may be bad even above and beyond smoking, poor diet and stress.”

And, remember when you used to approach any endeavor with a little mischievous glee? Nothing makes us more creative, more relaxed, more youthful and mindfully present than a sense of play.  So, play your way to eternal youth.