The Brain Declines from Age 40: But Don't Fire the Middle Aged Just Yet

An interesting report out today showing that declines in mental function start rather earlier in life than we have all previously thought. It’s actually in our 40s that cognitive function starts to decline.

Memory, reasoning and comprehension skills – collectively known as cognitive function – all tend to get worse as we enter middle-age, found the study of thousands of Whitehall civil servants.

No, this doesn’t quite mean that you should go out and fire everyone over 40 right now. Quite part from the fact that in much of the developed world that would be illegal on age discrimination grounds.

The researchers quantified the mental abilities of over 7,000 civil servants between 1997 and 2007. Aged between 45 and 70 at the start, they were asked to undertake a series of tests at the beginning and end of the 10-year period.

For example, in one test they were asked to recall as many words beginning with ‘S’ and as many animal names as possible from a list of words read to them. Other tests examined their vocabulary, aural and visual comprehension.

The researchers found those aged 45 to 49 in 1997 experienced a 3.6 per cent decline in cognitive function over the decade.

The real reason you don’t want to get rid of everyone in this age group or over is because cognitive function isn’t actually the only thing that you’re employing people for. Yes, of course, a certain amount of it is necessary and lots of it certainly desirable. But it still isn’t the only thing that is being paid for. The other things, like wisdom, experience, knowledge, they’re also important.

There’s a useful analogy here from dance (in fact, from almost any sport or physical activity but I first saw it in relationship to a film with Baryshnikov and Gregory Hines). Everyone knows that dancers are at their physical peak in their early 20s. Possibly even younger for women at times: but everyone also knows that dancers are not at their prime at that age. While physique and sheer athletic ability might decline from then onwards there’s also an increase in technique, artistic experience, going on as well. And the reason that dancers are often said to peak in their early 30s (that sweet spot where Hines and Baryshnikov were when they made the movie, thus the reference to it) is where the increase in skill and experience is still just ahead of the decrease in pure physical ability.

Retirement comes when that is no longer the case, when the physical decline is happening faster than any increase in experience is making up for. For dancers and other athletes that comes sooner in life than it does for the rest of us.

But which of us wouldn’t at least claim that we learnt more than 3.6% more between 45 and 49 which would cover that decline in pure brain function?

On the other hand, if this is all too close to home (my own 40th disappeared in the rear view mirror some time ago) we can take comfort in the fact that this research was carried out with civil servants and therefore may well not apply to human beings at all.