{"text":[[{"start":0.5,"text":"When I was in my late twenties, I remember reading a pop science article which told me that I had already passed my cognitive peak. I had barely started my career and already my brain was apparently on an inexorable downward slope."}],[{"start":1,"text":"I shrugged it off at the time, but as I enter my forties, I find the idea more depressing. How many years before people begin to tell me encouragingly that what I lack in cognitive skill I make up for in “wisdom”? Am I going to have to start doing crosswords to slow my inevitable decline?"}],[{"start":1.5,"text":"Not necessarily. A new longitudinal study has painted a very different picture of what happens to people’s cognitive skills as they age. The OECD runs a programme in which it tests the literacy and numeracy skills of adults aged 16 to 65 across 39 countries. Germany, uniquely, retested a panel of participants three-and-a-half years later."}],[{"start":2,"text":"Based on this data, a group of academics found that people’s skills did not appear to peak in their twenties or thirties. In fact, they continued to increase up to about 45-years-old in literacy and about 40 in numeracy."}],[{"start":2.5,"text":"Even more interestingly, the researchers split the sample into people who reported that they used their skills frequently in daily life, and those who reported that they didn’t. People with above-average skill usage at work and at home did not experience a decline in their skills at all, even at older ages. Indeed, people in this “high skill usage” group who also had degrees and white-collar jobs actually saw their scores continue to improve."}],[{"start":3,"text":"For Ludger Woessmann, an economics professor at the University of Munich and one of the study’s authors, the conclusion is that “if we keep on using and entertaining our brains” then their trajectories are “much more malleable” than many people believe. “If anything, there are these groups of people where you keep improving,” he added. “This is much more heartening.”"}],[{"start":3.5,"text":"Of course, this is just one study over the course of a few years in one country. Can it be extrapolated, or am I smoking “copium”, as I believe The Young People of Today would put it?"}],[{"start":4,"text":"Yes and no, says John Rowe, professor of health policy and ageing at Columbia University. If you look at the whole body of work on this question across different populations, genders and countries, there are “certain functions that are clearly decreasing substantially with age after their peak, and the peak varies from 20 to 30 to 40,” he told me."}],[{"start":4.5,"text":"One of these functions is cognitive speed. Another is the ability to incorporate and act on multiple inputs at once. That said, other aspects of intelligence do seem to continue to improve with age, such as vocabulary."}],[{"start":5,"text":"And, as the German study found, there is “tremendous variability” in how different people age, Rowe said. “When you’re 80 . . . some of you are going to score like the average 40-year-old, and some of you are going to score very badly”. What’s more, “the proportion of people who continue to score well is quite high.”"}],[{"start":5.5,"text":"He once took a cohort of healthy 75-year-olds and studied them again six years later. Their average score was much lower, but “a full 25 per cent of them hadn’t changed”."}],[{"start":6,"text":"What makes the difference? Unsurprisingly, a whole range of things, including genes, diet, work, socio-economic background and health. How much you keep using your brain matters, too, as the German study suggests. But Rowe told me that doing a daily “brain training” puzzle doesn’t do much. “If you do a lot of crosswords, you know what’s going to happen? You’re going to get very good at crosswords, but it doesn’t generalise.”"}],[{"start":6.5,"text":"He said three things have much wider benefits for cognition: exercise, learning a language and learning a musical instrument. On a sabbatical a decade ago, he went to a language centre and asked if he could study a language intensively, five days a week. “She said ‘what language?’ and I said ‘I don’t care!’”"}],[{"start":7,"text":"Rowe is now 80. Even as a 40-year-old, I think I would worry that my brain was no longer sponge-like enough to learn a new language. But those sorts of assumptions are part of the problem."}],[{"start":0,"text":"Some laboratory studies suggest that older adults tend to underestimate the power of their memory, for example, and therefore shy away from using it in certain tasks, even though they are capable of doing so. In that sense, thinking your brain is on a downward slope can be self-fulfilling."}],[{"start":21.4,"text":"As we age, perhaps the best thing we can do is to stop believing in the inevitability of our cognitive decline. Even if it is copium, it might just work."}],[{"start":21.9,"text":"sarah.oconnor@ft.com"}],[{"start":null,"text":"