âYour brain isnât fully formed until youâre 25â: A neuroscientist demolishes the greatest mind myth
You may heard that if youâre under 25, your brain isnât fully developed yet. It's an adage supposing that individuals under 25 canât think things through or make rational decisions, and so are less responsible than older folk. This logic has now formed the basis of official government advice, sentencing, and more.
The only problem with this fact is⊠itâs not a fact. Never has been. No matter how many TikTokers insist otherwise.
Why is it wrong? Well, lots of reasons.
Thereâs no real evidence for the âage 25â claim
Despite its prevalence, thereâs no actual data set or specific study that can be invoked or pointed at as the obvious source of the claim that âthe human brain stops developing at age 25â.
It could be a misunderstanding, stemming from brain scanning studies which looked at subjects up to the age of 25. But thatâs like saying sprinters can only run 100 metres at most after watching the 100m final at the Olympics. The limit is imposed by the context, not biology.
Others argue that 25 is simply a pleasing-sounding number, and the idea caught on purely as a result. Stranger myths have spread this way â looking at you, âwe only use 10 per cent of our brainsâ.
âDevelopingâ does not mean ânon-functioningâ
Just because age 25 isnât some firm endpoint for development, it doesnât mean the brain isnât developing before then. Because it is. Itâs developing after that age too, in many cases.
Exactly when âdevelopingâ and âmaturationâ ends is tricky to pin down. The human is essentially an assemblage of many different regions, of varying degrees of complexity, maturing at different rates.
But even if we focus on the frontal lobe, where all the reasoning and thinking occurs (mostly), itâs still very important to remember that brain development isnât like the building of a house. You don't have to wait until all the walls and floors are done, the plumbing is sorted out and the electrics are installed before it can be used. Before you can actually live in it.
Itâs more like evolution. There were many evolutionary species between the primitive rodent-like creatures that were the first mammals, and modern-day humans. But each of these stages was, at that point, a fully functional, successful species. There were no unworkable intermediary species, like a rat's torso on a pair of massive bipedal legs.
So it is with the human brain. Even if you believe that people under 25 arenât âas goodâ at decision-making as older people, it doesnât mean they canât do it, or shouldnât be allowed to.
I, for example, am nowhere near as strong as someone like renowned British Worldâs Strongest Man competitor Eddie âThe Beastâ Hall. But that in no way disqualifies me from bringing the heavy shopping in from the car.
If it is true, we need serious societal upheaval
Even if itâs entirely well-intended, basing official legislation or government policy on the premise that the human brain is not sufficiently developed before age 25 sets a very significant precedent. If 25 is seen as the legal minimum where you can be trusted to think things through and make decisions, then that would logically apply to all facets of life.
For instance, countless people choose and complete their degrees and even PhDs long before their mid-twenties. Also, the UK is the only country in Europe that allows recruitment in the military of individuals aged under 18. And they must serve until theyâre 22!
Football academies can accept players from age 9. And 25 is closer to retirement age for a professional footballer, as well as many other top athletic pursuits.
hese are just three examples of people being trusted to make massively life-affecting decisions long before their brains are âfully developedâ. And if we start insisting that anyone under 25 is too underdeveloped to do this, that has serious ramifications.
Letâs take it further. Suppose the argument is that your reasoning abilities must function at maximum before you can decide anything important. In that case, we need a maximum age too, not just a minimum.
Development is one thing, but thereâs also cognitive decline. Because age and entropy canât be avoided. Thatâs why people from middle age and later show reduced mental abilities. However, some studies suggest our cognition truly starts to decline in our twenties. This would suggest thereâs maybe a window of a few months when we can be âtrustedâ to make decisions.
Of course, this is a wildly reductionist, overly simplistic perspective. But the same can be said about the whole âunder 25â thing. Even if it were true. Which is mostly isnât. And you donât need to be a certain age to grasp that.