Are we getting slower? The answer should concern us all.
A few years ago I did a television program called The Great British Intelligence Test where we measured the nation’s intellectual capacity and carried out the largest intelligence experiment of its kind.
More than a quarter of a million people took our special IQ test, developed for us by scientists at the Department of Brain Sciences at Imperial College London. (You can see what we put people through by searching online for ‘Michael Mosley IQ Test.’)
Unsurprisingly, we found that when it came to solving problems, people in their twenties were the best at it; They have more knowledge on their side than, say, a teenager, but their brains also work faster than those of middle-aged or older people.
The reason problem-solving ability declines with age is, in part, related to how well insulated the connections between brain cells are.
Dr. Michael Mosley made a television show called The Great British Intelligence Test.
As we age, the myelin sheath surrounding the brain’s wiring becomes thinner and communication between our neurons becomes slower. Our brains literally slow down.
But there was good news for seniors; While other cognitive abilities decline with age, verbal ability increased and peaked in people in their 70s. Interestingly, cat lovers scored higher on verbal ability than dog lovers (although this may have been a coincidence), as did book readers and people who liked fruits and vegetables.
But the biggest surprise came much later, long after the show had aired on television.
That’s because the test went online in 2019, before the Covid pandemic swept the world, and researchers continued collecting data well into 2020, when the outbreak was at its worst.
At this point they had included questions about whether people had had Covid and, if so, how it had affected them.
They found that people who had been infected scored lower on IQ tests, particularly when it came to something called executive function, a measure of mental abilities such as memory, flexible thinking and self-control. If your executive function is impaired, this can make it difficult for you to concentrate, follow instructions, and manage emotions.
The team has since completed a larger study involving more than 112,000 people, which was published last month in the New England Journal of Medicine.
This confirmed the long-term impact that Covid can have on our brain. People who had a mild infection lost a couple of IQ points, but those who developed long Covid saw an average drop in IQ of about six points.
And the results of this study fit with another, more worrying trend: that IQ scores have been falling around the world since the 1970s. In a 2018 study published in the Proceedings of the National Academy of Sciences, researchers analyzed the IQ scores of young men in Norway, recorded when they were recruited for compulsory military service. Over a 40-year period, starting in 1970, there was a steady decline of about seven points per generation.
This phenomenon has since been recognized in other countries, including the United States and the United Kingdom.
While no one knows exactly what is happening, there is a suggestion that it could have to do with rising levels of obesity and our increasing reliance on ultra-processed foods, which are bad for the brain.
Being struck by an infectious disease, particularly one that persists (like Covid), is also a sure way to lower your IQ score.
There is also growing concern, among some researchers I have spoken to, that the rise of artificial intelligence will increase downward pressure on human intelligence, as we increasingly rely on machines to do our thinking for us.
So what can you do to keep your brain in good shape?
There is plenty of evidence that eating a healthy diet can make a big difference. A study of people in their 70s by the University of Edinburgh in 2021 found that those who followed a Mediterranean diet (rich in olive oil, nuts, vegetables and fish) scored the highest on a variety of memory and thinking tests .
More surprisingly, playing computer games also appears to be good for improving cognitive skills. That’s certainly what we found in The Great British Intelligence Test, a finding supported by a recent, more rigorous study, published in JAMA Network Open in 2022.
Scientists at the University of Vermont analyzed data from nearly 2,000 children and found that those who reported playing fast-paced video games for three hours a day or more performed better on tests of impulse control and working memory than children who said they never did. They had played video games. .
Not only that, but brain scans showed they had increased activity in regions associated with attention and memory, a result of all those hours spent trying to shoot things and avoid getting shot.
And last but not least, keep challenging yourself mentally. There is plenty of evidence that taking up new hobbies, like dancing or painting, will keep your brain young.
Conversely, withdrawing from the world can cause brain shrinkage, a reduction in brain cell connections, and even a drop in hormone levels in the brain that are essential for long-term repair and maintenance.
I intend to do everything I can to keep my neurons firing as long as possible and, as the poet Dylan Thomas said, “rage, rage against the dying of the light.”
One of the most difficult things to treat is a chronic wound, such as those caused by type 2 diabetes.
Now, researchers at the University of Sheffield are using ionized gas (electrically charged gas) to treat chronic wounds: the gas creates a chemical cocktail in the wound, which helps kill bacteria and speed up healing. With antibiotic resistance on the rise, this could be a game-changer.
Your dog really understands
Our dog, Tari, died a couple of months ago and I still find myself yelling “walkies” as I walk out the front door, forgetting that she’s gone.
I’ve often wondered if she understood the word “walkies,” or if it was my tone of voice and demeanor (i.e., the fact that I was standing by the front door with a leash in my hand) that gave her the cold shoulder. clue. .
A recent study suggests that dogs understand us better than we think. Researchers at Budapest’s Eotvos Lorand University monitored dogs’ brain waves as they listened to their owners say words they assumed they knew, such as “ball.”
They found that when dogs were given a toy that matched the word their owner said, their brain activity was different than when they were given something that didn’t match.
The researchers said this is proof that dogs really understand the meaning of words. Our canine friends are even more remarkable than most of us already realize.
Bitter-tasting vegetables can improve your mood
Many people have difficulty eating bitter green vegetables such as kale, chard, and chicory. However, these are particularly good for us, and here’s more information on why.
Bitterness is one of our five “basic” tastes (the others are sweet, salty, sour, and umami). Humans are particularly sensitive to bitter tastes, probably because bitterness is often associated in the natural world with poison, something that should be avoided.
However, bitterness is also a sign that foods are rich in beneficial plant compounds called polyphenols. Recent research by the Shibaura Institute of Technology in Japan provided fascinating information about why polyphenols are so good for us.
They point out that we have taste receptors throughout the body. You find them, for example, in the intestine, where they respond to the polyphenols you have ingested by releasing hormones that improve your blood sugar levels and your mood.
Men even have similar sensory receptors in their testicles that appear to play a role in the production of healthy sperm. That could explain why men who eat lots of green, bitter leafy vegetables tend to have higher sperm counts and better sperm motility.
Something to keep in mind the next time you buy vegetables.