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If you feel like your thinking has been getting a bit foggier as you've gotten older — like you're just... slowing down… you're not alone. This happens eventually to nearly everybody.

But researchers have been looking into exactly how minds change as people age, and they've got a few ideas as to how to slow those changes down a bit. As you get older, your brain — like your hair — tends to thin. The average person's brain loses volume at a rate of about 5% per decade after age 40 — it seems like neurons just get old and die — and researchers think this may explain why people's thinking also gets slower and fuzzier as they get older.

But there's actually some debate about how bad the normal decline in brain functioning with age really is. And newer research suggests it might not be as bad as we first thought. The easiest way to ask this question is to just give a variety of different memory and intelligence tests to adults of varying ages.

And when researchers do that, they see a pretty clear pattern emerge, though it does depend on what kind of tests you use. The story doesn't look good for things like speed of reasoning and perception, pattern recognition, and short term memory for words said aloud. And these declines don't just happen when you're in your 80s.

People in their late 30s score significantly lower than people in their 20s. Yeah, really looking forward to that. But the story is very different when participants are given a vocabulary test, or asked to do crosswords.

In those, scores improve with age and hold steady even as other abilities decline later in life. Psychologists think that's because vocabulary is a kind of crystallized intelligence, or knowledge that's the product of thinking and learning over the years. Other kinds of crystallized intelligence likely follow a similar pattern.

For example, older chess players pick moves just as well as younger players, despite differences in their abilities to remember patterns on the chess board. But crystallized intelligence varies a lot from person to person based on life experience and expertise, so it's harder to test different aspects of it across big populations. Most of the tests where age-related declines are seen, though, fall into the category of fluid intelligence — things that help you think on your feet to process new information.

So psychologists generally think that for those without Alzheimer's or other kinds of dementia, growing old means losing some fluid intelligence while keeping crystallized knowledge. You might forget where you put your keys, but you still know what your keys are for. And there are areas that might improve with age — like social reasoning: the ability to infer other people's feelings and intentions.

When researchers presented people with stories of social conflicts and asked how they'd unfold, they found that the older participants were more likely to employ complex reasoning, emphasize multiple people's perspectives and allow for compromise. So it's not like everything goes downhill. And even the declines usually seen in tests comparing old and young people may not be so guaranteed.

Some recent research suggests these declines might not appear until later in life — after age 60 or later — or that some fluid abilities can be retained or even improved. These studies have looked at cognitive abilities longitudinally, meaning measuring the same people over time. This can avoid the problem of mistaking a generational difference for an age-related difference.

But, people often drop out, and that may mean those who suffer more problems don't stay in the study long enough to be included in the oldest age groups, skewing the results. And even if there's less decline than we thought, there are still some things that just seem to go as you get older, which a lot of people probably wish didn't. Unfortunately, so far, there doesn't seem to be a way to turn back the clock.

But there are some things that can slow down age-related declines, or at least delay them. A long-standing recommendation has been "use it or lose it" — basically, that you should practice with the skills you want to maintain — and there's some research to support that idea. A good example is a 1992 study that took 35 subjects over a year and gave them a total of 38 training and practice sessions in a memory technique called the method of loci.

The results were optimistic: the older adults didn't show the declines in working memory that were typical for their age group. But, unfortunately, it didn't really improve things either — no matter what, the younger participants always did better. Other studies similarly suggest that regular practice can delay declines, but can't really reverse them.

Plus, the benefits are really only for the exact thing you're practicing. Research shows that regular training on specific cognitive abilities like memory or processing speed really only improves that ability — it doesn't help others or improve cognition overall. In fact, if you want to more generally keep your mind sharp, studies suggest being active in other ways could be a bigger help than specific mental exercises.

Longitudinal studies of cognitive skills in older adults show that things like social engagement and aerobic exercise have a strong relationship with maintaining function. And a meta-analysis done in 2003 found that across the board, exercise improved cognitive abilities compared to control groups. But not all skills improved equally.

Like, exercise groups did a lot better on executive function tasks — but only a little bit better on processing speed. Whether we'll ever be able to reverse age-related declines and give 80 year olds the sharpness of 20 year olds remains to be seen. But in the meantime, it seems like going out and having some fun exercising with friends helps a little more than staying home with crosswords.

And hey — if you go out during the day and do that crossword over breakfast or before bed, you can have the best of both worlds! Thanks for watching this episode of SciShow Psych! And thanks especially to our patrons on Patreon.

It takes a lot of people behind the scenes to make every video we put out, and we wouldn't be able to have those people if it weren't for the support of our patrons. If you want to join our community of supporters on Patreon and help us keep making free, educational psychology videos, you can head over to Patreon.com/SciShow [ ♪OUTRO ].