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).
At the same time as a group of French parents and teachers have called for a two-week boycott of homework (despite the fact that homework is officially banned in French primary schools), and just after the British government scrapped homework guidelines, a large long-running British study came out in support of homework.
I’ve discussed on a number of occasions the effects that stereotypes can have on our cognitive performance. Women, when subtly reminded that females are supposedly worse at math, do more poorly on math tests; African-Americans, when subtly reminded of racial stereotypes, perform more poorly on academic tests. And beliefs about the effect of aging similarly affect memory and cognition in older adults.
Except in the cases of stroke or traumatic brain injury, loss of cognitive function is not something that happens all at once. Cognitive impairment that comes with age may be thought of as belonging on a continuum, with one end being no cognitive impairment and the other end being dementia, of which Alzheimer's is the most common type.
We all know that lack of sleep makes us more prone to attentional failures, more likely to make mistakes, makes new information harder to learn, old information harder to retrieve ... We all know that, right? And yet, so many of us still go to bed too late to get the sleep we need to function well. Of course, some of us go to sleep early enough, we just can’t get to sleep fast enough, or are prone to waking in the night. (Personally, I can count the times I’ve slept through the night without waking in the last fifteen years on my fingers).
The thing to remember about Ericsson’s famous expertise research, showing us the vital importance of deliberate practice in making an expert, is that it was challenging the long-dominant view that natural-born talent is all-important. But Gladwell’s popularizing of Ericsson’s “10,000 hours” overstates the case, and of course people are only too keen to believe that any height is achievable if you just work hard enough.
The much more believable story is that, yes, practice is vital — a great deal of the right sort of practice — but we can’t disavow “natural” abilities entirely.
We forget someone’s name, and our response might be: “Oh I’ve always been terrible at remembering names!” Or: “I’m getting old; I really can’t remember things anymore.” Or: nothing — we shrug it off without thought. What our response might be depends on our age and our personality, but that response has nothing to do with the reason we forgot.
When considering what will be the most effective strategies for you, don't forget the basic principles of memory:
(1) Repetition repetition repetition
The trick is to find a way of repeating that is interesting to you. This is partly governed by level of difficulty (too easy is boring; too difficult is discouraging). The point is to find an activity (more than one, in fact), which enable you to hold on to your motivation through sufficient repetitions to drive them into your head. Bear in mind, too, the importance of:
(2) Changing context
Elaborative interrogation is a strategy to help you remember meaningful information. The idea behind the strategy is that relevant prior knowledge is not always readily activated when you are trying to learn new information, and sometimes help is needed to make the right connections. The strategy requires you to go beyond the information given to you and to construct reasons for the relationships between bits of information.
After Alzheimer's disease, the second most common neurodegenerative disorder is Parkinson’s disease. In the U.S., at least 500,000 are believed to have Parkinson’s, and about 50,000 new cases are diagnosed every year1 (I have seen other estimates of 1 million and 1.5 million — and researchers saying the numbers are consistently over-estimated while others that they are consistently under-estimated!). In the U.K., the numbers are 120,000 and 10,0002.