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Genes

Several genes have been implicated in Alzheimer's, but the big one is the e4 allele of the ApoE gene (on chromosome 19). This variant is found in about a quarter of the population.

Having it doesn't mean you are foreordained to develop Alzheimer's, but it certainly increases the risk substantially. The risk goes up considerably more if both of your genes are the e4 variant (remember you inherit two: one from each parent).

Having trouble sleeping is perfectly normal, especially as we age. It’s estimated that half of those older than 55 have trouble getting to sleep or staying asleep.

What to do if your sleep is poor

Let’s start with the easiest situation: you’re not getting enough sleep because you wilfully go to bed too late to achieve your needs.

I recently reported on a finding that memories are stronger when the pattern of brain activity is more closely matched on each repetition, a finding that might appear to challenge the long-standing belief that it’s better to learn in different contexts. Because these two theories are very important for effective learning and remembering, I want to talk more about this question of encoding variability, and how both theories can be true.

If you have a numbered list to memorize, the best mnemonic strategy is the pegword mnemonic. This mnemonic uses numbers which have been transformed into visual images. Here's the standard 1-10 set.

pegs

I add two more:

There hasn't been a lot of research into the effects of herbs and spices on cognition and the brain, unfortunately. But on the positive side, the risk of side-effects is very low, so we don't need a lot of evidence for it to be worth trying.

I was listening to a podcast the other day. Two psychologists (Andrew Wilson and Sabrina Galonka) were being interviewed about embodied cognition, a topic I find particularly interesting.

The conventional view of brain development has been that most of this takes place in utero and in the first three years, with the further development continuing until the brain is fully mature at around 10-12 years of age. The turbulence of adolescent behavior has been deemed to be mostly caused by hormonal changes. Piaget, who identified four stages of cognitive development, assessed that his highest stage — that of formal, abstract reasoning — occurred around 13-14 years (although not everyone reaches this level, which requires appropriate education).

Let's look a little deeper into the value of mnemonics for knowledge acquisition. By “knowledge acquisition”, I mean the sort of information you learn from textbooks — information that is not personal, that you need for the long-term.

In this context, I believe the chief value of mnemonic strategies is to help you recall information that needs to be remembered in a particular order. Thus we use mnemonics to help us remember the order of the planets, the order of musical notes on the stave, the order of the colors in a rainbow.

Does photographic memory exist?

"Photographic" or eidetic memory is said to occur in some 8% of children, but almost all of these grow out of it. The phenomenon is extremely rare in adults, and indeed the very existence of photographic memory is still somewhat contentious. However, it may be that particular brain abnormalities can lead to ways of processing information that are dramatically different from the normal (see the case of Kim Peek).