Let’s talk about the cognitive benefits of learning and using another language.
In a recent news report, I talked about the finding that intensive learning of a very novel language significantly grew several brain regions, of which two were positively associated with language proficiency. These regions were the right hippocampus and the left superior temporal gyrus. Growth of the first of these probably reflects the learning of a great many new words, and the second may reflect heavy use of the phonological loop (a part of working memory).
There are several aspects to this study that are worth discussing in the context of using language learning as a means of protecting against age-related cognitive decline.
First of all, let me start with a general reminder. We now know that, analogous to muscles, we can ‘grow’ specific brain regions by working them. But an adult brain is confined by the skull — growth in one part is generally at the expense of another part. So, unlike body-building, you can’t just grow your whole brain!
This suggests that it pays to think about the areas you want to improve (which goes right back to the first chapter of The Memory Key: it’s no good talking about improving ‘your memory’ — rather, you should pick the memory tasks you want to improve).
One of the big advantages of growing the parts of the brain involved in language is that language is so utterly critical to our intellectual ability. Most of us use language to think and to communicate. There’s a reason why so many studies of older adults’ cognitive performance use verbal fluency as the measure!
But, in the same way that the increase in London cab drivers’ right posterior hippocampus appears to be at the expense of the anterior hippocampus, the growth in the right hippocampus may be at the expense of other functions (perhaps spatial navigation).
Is this a reason for not learning? Certainly not! But it is perhaps a reminder that we should be aiming for two things in preventing cognitive decline. The first is in ‘growing’ brain tissue: making new neurons, and new connections. This is to counteract the shrinkage (brain atrophy) that tends to occur with age.
The second concerns flexibility. Retaining the brain’s plasticity is a vital part of fighting cognitive decline, even more vital, perhaps, than retaining brain tissue. To keep this plasticity, we need to keep the brain changing.
Here’s a question we don’t yet know the answer to: how much age-related cognitive decline is down to people steadily experiencing fewer and fewer novel events, learning less, thinking fewer new thoughts?
But we do know it matters.
So let’s go back to our intensive language learners growing parts of their brain. Does the growth in the right hippocampus (unfortunately we don’t know how much that growth was localized within the right hippocampus) mean that it will now remain that size, at the expense, presumably, of some other area (and function)?
No, it doesn’t. As far as language is concerned, the hippocampus is primarily a short-term processor. As those new words are consolidated, they’ll move into long-term memory, in the language network across the cortex. Once the interpreters stop acquiring new vocabulary at this rate, I would expect to see this region reduce. Indeed (and I am speculating here), I would expect this to happen once a solid ‘semantic network’ for the new language was established in long-term memory. At this point, new vocabulary will be more and more encoded in terms of that network, and reliance on the short-term processes of the hippocampus will become less (although still important!).
I think that intensity is important. Intensity by its very nature is rarely maintained. People at the top of their field — champion sportspeople, top-ranking musicians, ‘geniuses’, and so on —they have to maintain that intensity as long as they want to stay at the top, and I would expect their brains to show more enduring changes (that is, particular regions that are unusually large, and others that are smaller than average). For the rest of us, any enduring changes are less marked.
But making those changes is important!
In recent years, research has come to suggest that, although regular moderate exercise is highly beneficial for physical and mental health, short bouts of intense activity have their own specific benefits above and beyond that. I think the same might be true for mental activity.
This may be particularly (or differently) true as we get older, when it does tend to get harder to learn — making (relatively) short bouts of intensive study/learning/activity so vital. We need that concentrated practice more than we did when we were young and learning came easier. And concentrated practice may be exactly the way to produce significant change in our brains.
But we don’t need to worry about becoming ‘muscle-bound’ — if we learn thousands of new words in a few months (an excellent step in acquiring a new language), we will then go on to acquire grammar and practice reading and writing whole sentences. The words will consolidate; different language skills will build different parts of the brain; those areas no longer being intensively worked will diminish (a little).
Moreover, it’s not only about growing particular regions, it’s also very much about building new or stronger connections between regions — building new networks. Because language learning involves so many regions, it may be especially good for that aspect too (see, for example, another recent news report, on how language learning grows white matter and reorganizes brain structures).
The important thing is that your brain is changing; the important thing is that your brain keeps changing. I think intensive periods of new learning are the way to achieve this, interspersed with consolidation periods.
As I’ve said before, variety is key. By providing variety in learning and experiences across tasks and domains, you can keep your brain flexible. By providing intense focus for a period, you can better build specific ‘mental muscles’.
