Impaired vision is common in old age and even more so in Alzheimer’s disease, and this results not only from damage in the association areas of the brain but also from problems in lower-level areas. A major factor in whether visual impairment impacts everyday function is contrast sensitivity.

Contrast sensitivity not only slows down your perceiving and encoding, it also interacts with higher-order processing, such as decision-making. These effects may be behind the established interactions between age, perceptual ability, and cognitive ability. Such interactions are not restricted to sight — they’ve been reported for several senses.

In fact, it’s been suggested that much of what we regard as ‘normal’ cognitive decline in aging is simply a consequence of having senses that don’t work as well as they used to.

The effects in Alzheimer’s disease are, I think, particularly interesting, because we tend to regard any cognitive impairment here as inevitable and a product of pathological brain damage we can’t do anything much about. But what if some of the cognitive impairment could be removed, simply by improving the perceptual input?

I talk a lot about how working memory constrains what we can process and remember, but there’s another side to this — long-term memory acts on working memory. That is, indeed, the best way of ‘improving’ your working memory — by organizing and strengthening your long-term memory codes in such a way that large networks of relevant material are readily accessible.

Oddly enough, one of the best ways of watching the effect of long-term memory on working memory is through perception.

Perception is where cognition begins. It’s where memory begins. But here’s the thing: it is only in the very beginning, as a newborn baby, that this perception is pure, uncontaminated by experience.

‘Uncontaminated’ makes it sound bad, but of course the shaping of perception by experience is vital. Otherwise we’d all be looking around wide-eyed, wondering what was going on. So we need to shape our perception.

Children learn. It’s what they do. And they build themselves over the years from wide-eyed baby to a person that walks and talks and can maybe fix your computer, so it’s no wonder that we have this idea that learning comes so much more easily to them than it does to us. But is it true?

There are two particular areas where children are said to excel: learning language, and learning skills.

Years ago I reported on a 2003 study that challenged the widespread view that young children learn language more easily than anyone older, in regard to vocabulary. Now a new study suggests that the idea doesn’t apply to grammar-learning either.

I recently reported on a study showing how the gestures people made in describing how they solved a problem (the Tower of Hanoi) changed the way they remembered the game. These findings add to other research demonstrating that gestures make thought concrete and can help us understand and remember abstract concepts better.

For example, two experiments of children in late third and early fourth grade, who made mistakes in solving math problems, have found that children told to move their hands when explaining how they’d solve a problem were four times as likely to manually express correct new ways to solve problems as children given no instructions. Even though they didn’t give the right answer, their gestures revealed an implicit knowledge of mathematical ideas, and the second experiment showed that gesturing set them up to benefit from subsequent instruction.