Many believe cognitive decline is inevitable with age.
A new study challenges this, suggesting decline isn't a given.
Transcript:
Ian Sample
Do you like to hunker down with a brain-straining cryptic crossword to scale the intellectual heights of a highbrow novel or plough through sudokus to keep your faculties sharp? These are all things we do in the hope of slowing what we perceive as the inevitable decline in our cognitive abilities as we get older. But a new study into human brainpower suggests that the decline we've come to expect in later life isn't necessarily a given.
Ludger Wößmann
The real big takeaway here is that there's no natural law whatsoever that would dictate skill decline with age. So (Time 0:02:11)
Previous Consensus on Cognitive Decline
Previous research suggests cognitive skills decline from age 30.
This is based on cross-sectional studies comparing different age groups at one time.
Transcript:
Ian Sample
So, Ludger, you've done some work which challenges some of our previously held ideas about how cognitive skills change with age. But first of all, what has the consensus been up until now?
Ludger Wößmann
I think the consensus so far was that cognitive skills pretty much start declining by age 30, if not earlier. And that comes from research where you just look at people at different ages at a given point in time, and you basically see that people who are 40 don't do as well on numeracy and literacy Tests than people aged 30, and people who are 50 don't do as well as people aged 40. (Time 0:03:23)
Limitations of Cross-Sectional Studies
Cross-sectional studies have limitations, as different age groups have varying experiences.
Wößmann's research uses longitudinal data, tracking individuals over time.
Transcript:
Ian Sample
So that's the evidence from just testing a whole cross-section of people of different ages. And that suggests that cognitive skills start declining from the age of 30 onwards. Although in my case, I'm absolutely been in decline since about 14 years old. Now, before we get to your own work on this, you're an economist rather than a neuroscientist. Why are you interested in this?
Ludger Wößmann
So the point is that these type of cognitive skills, math skills, reading skills, also science skills really, have been shown to be super important for economic prosperity, both of Individuals, but also in terms of the long-run economic growth of entire economies. And then if this pattern of decline is really the true effect of age, this is really concerning for societies with rapidly aging populations, as many industrialized economies have Right now. (Time 0:04:05)
Impact of Skill Usage
The study found skills increase into the 40s, then decline slightly in literacy, more in numeracy.
Skill usage is key: high users see no decline even up to 65.
Transcript:
Ian Sample
A totally different picture from the cross-section. You were also able to measure in these data how frequently people were using particular skills.
Ludger Wößmann
So where did those data come from? Right. The other thing is that this PIAG dataset, they ask people about lots of things that they're doing both at work and at home. And so they have lots of items that ask, like, how often do you read directions or instructions? How often do you read letters or emails, newspapers, and so on and so forth? And then actually on the math side, they ask you, how often do you have to calculate prices, use fractions, use a calculator or prepare charts or tables. And so from these, we basically construct an index of how often different people use math skills and how often they use reading skills at home and at work.
Ian Sample
You pulled all these data together then, Luca.
Ludger Wößmann
What did your analysis show? So there's really two main results that we find. So first of all, the average skills actually increased strongly into the 40s. So really, if you look at how people do over time, even into the 40s, people keep increasing their skills. And then after that, we see slightly decreasing skills in literacy and more strongly decreasing skills in numeracy, even though even in numeracy, it doesn't go below levels that you Are at, say, in your mid-20s. So that's the first part of the results. And then the second part relates to these skill usage methods that you just referred to. So what we basically see is the huge differences and how your skills change over time, depending on whether you use skills often or not. (Time 0:07:00)
Skill Usage Across Occupations
White-collar workers tend to use skills more than blue-collar workers, impacting cognitive decline.
High skill users, even in blue-collar jobs, show less decline.
Transcript:
Ian Sample
But also for people who regularly use their maths and literacy skills, they can stay just as sharp until at least 65. But Luca, who is experiencing decline? And who seems to be most protected from that? I mean, these people are clearly doing different things at work and at home, right? That's right.
Ludger Wößmann
And we see these patterns like quite similarly for whether we look at usage at home and usage at work. And so we see, on average, that white-color workers are more likely to use both reading and math skills than blue-color workers. And so for these groups, you see the expected patterns. But even more importantly, even within these groups, among white-color workers, there are some people who use these skills often and some who don't. And the same among blue-collar workers. And we see that even within these groups, that makes a huge difference. They actually are not going to decline even until age 65. (Time 0:09:14)
Gender Differences in Numeracy
Men tend to use numeracy skills more than women, showing less decline.
The reasons for this difference remain unclear, potentially related to job types.
Transcript:
Ian Sample
These differences you've just described between the regular users and the less regular users, if I can put it that way.
Ludger Wößmann
But you also saw quite a difference between males and females. Can you take me through that finding? Yeah, that's kind of interesting as well. So in reading, you don't see literally any differences in skill usage between men and women, but there's a real difference in numeracy, and that's quite surprising. So we actually do see that men are more likely to use numeracy skills than women are. But that actually can only explain some of the difference in how their skills actually change over their lives, where we see that actually male skills do not decline even at medium ages, Whereas women's numeracy skills decline much more strongly and at earlier ages. (Time 0:10:30)
Use It or Lose It
Cognitive decline is not inevitable; it depends on skill use.
Regularly challenge yourself with reading, math, and other cognitive tasks.
Transcript:
Ian Sample
These results? And it seems that they certainly challenge this idea that cognitive decline is something that we all have ahead of us. Well, yeah.
Ludger Wößmann
So I think the real big takeaway here is that there's no natural law whatsoever that would dictate skill decline with age. What we see is actually, on average, skills actually increase into the 40s. And then after that, it really depends strongly on whether you use your skills, so you constantly challenge what you are doing, or if you don't. So if you don't use it, you lose it. (Time 0:11:30)
