Why EVERYONE over 40 forgets their PIN number

... but oldies are better at crosswords than their children! Decade by decade, how age affects your memory

memory might start getting worse in your 40s. But people often develop systems that allow them to get round it, like learning to put their keys in the same place.’

YOUR 50s: YOU’RE A QUIZ GENIUS

GOING upstairs to look for something, then forgetting what that something is, feels alarming. But such memory lapses are normal for the average fiftysomething.

The probable reason is that your prefrontal cortex — a brain area like the blackboard of the mind, which holds memories you only need to keep for a short time — continues to shrink with age, partly because narrowing of the arteries may mean blood flow to the brain is not as good as it was. However, it’s not all downhill. Your acquired knowledge means that in this decade you are more likely to be an asset for the pub quiz team, as well as a whizz at solving crossword puzzles.

The ability to recall general knowledge and remember the right words peaks between the ages of 45 and 55. although the reasons for this are not completely understood, a number of large-scale, long-running studies have found that vocabulary accumulates over time and is practised so much over the years that it doesn’t start to decline until much later in life, possibly because it is stored across a range of brain regions.

However, if you are a woman, your husband may have temporary edge over you — for a few years, at least. Men reach their peak performance at factual recall in their 50s, while women get there in their early 60s.

The most likely explanation for this is that women’s memories temporarily deteriorate during the menopause, which hits most women at around the age of 51.

Dr Marilyn Glenville, the author of Natural Solutions to Menopause, says: ‘In my clinic, women have told me how they read a page in a book and realise they can’t remember any of it, so they have to reread the page. These issues are very common.’

The reason is falling levels of the female sex hormone oestrogen in parts of the brain that affect concentration, recall and mood.

Dr Glenville says: ‘Women have oestrogen receptors in their brains, so as levels decline this can affect cognitive function.’

The effect is only temporary, though. a 2009 study published in the journal Neurology found that when women’s hormones started to settle after menopause, their memories were as good as before.

YOUR 60s: WHAT WAS HER NAME?

WE CALL them ‘senior moments’ and they do occur more often when we’re in our 60s.

Tip-of-the-tongue experiences, where you know a name but can’t quite recall it, happen about once a week for young adults under 30. for people in their 60s, it’s more like once a day.

The problem is simply that knowledge is stored in many different parts of the brain, and it now takes longer to make the connections and retrieve what you need.

So a memory lapse is unlikely to be anything serious. at the age of 65, less than one person in a thousand has developed alzheimer’s.

One thing that may make you forget a fact, number or name, though, is being interrupted.

Studies looking at images of brain activity in older adults have found they find it harder to re-engage if prevented from completing a task, such as reading a recipe or filling in paperwork. They are less able to ignore distractions, then focus once more on the same brain network they were using before, according to scientists at the University of California.

YOUR 70s: YOU NEED A SATNAV

NOW is the time to get really efficient at making lists.

If the average 79-year-old is given a string of ten unconnected words, he or she recalls only about five after a single reading, memory tests have shown.

Most 25-year-olds, in contrast, can recall almost all of them.

Professor Martin Conway, Head of Psychology at City University, in London, says: ‘at this age your expertise and experience of life can mask declines in memory. It’s only when a researcher with a word list comes along that the real state of your memory might be revealed.’

In this decade, you may also need to call on your car’s satnav more than you used to — even if you are travelling somewhere familiar.

Research has found that the visual memory you need to follow a route declines by 30 per cent by this age. Many seventysomethings also complain that it’s easier to remember an incident from decades ago than to recall what they had for dinner the day before.

That reason is that vivid, important life events — ‘flashbulb moments’ — are encoded in your brain when you experience a surge of feelings.

This reaction also triggers the amygdala, a primal part of the brain activated by powerful emotions, setting such occasions more firmly in your long-term memory.

In fact, if you look back over your life, the period you are likely to remember most clearly is your 20s, perhaps because most formative events happen then.

Professor alan Baddeley, Professor of Psychology at York University and the author of Working Memory, Thought and action, says: ‘It’s called the Reminiscence Bump. In your 20s you’re going to university, you’re starting your first job, you’re falling in love — all fairly striking events.

‘You don’t get so many of these major life events in your 40s, 50s and 60s. They also stand out because you think about them more.’

YOUR 80s: THINGS WE DON’T FORGET

ALTHOUGH the decline in memory does speed up now, mainly because the flow of blood and oxygen to the brain is not as good as it once was, only one person in six aged 80 and over has dementia, according to the alzheimer’s Society.

In fact, if you are worrying about your memory, it may be a sign that you have less to fret about.

Most dementia patients are taken to see doctors by worried family members who have begun to notice serious changes, while those affected are not themselves aware of the decline.

While a normal 80-year-old may forget where they put their keys, a dementia sufferer will forget what keys are for.

The good news is that it’s never too late to improve your memory.

Learning to play complex video games, taking regular exercise that stimulates the flow of blood to the brain, and eating oily fish have all been found to make an appreciable difference.

In this decade, the likelihood is that you will always be able to enjoy your favourite hobbies — because there is truth to the old saying that you never forget how to ride to bicycle.

Scientists have found that what is called procedural memory — the ability to recall routine skills such as cycling, playing tennis or swimming — does not fade with age. This is probably because lots of different parts of the brain, including the areas that don’t age badly, are used to recall how these activities are performed.