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).
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What is neurogenesis?
Neurogenesis — the creation of new brain cells — occurs of course at a great rate in the very young. For a long time, it was not thought to occur in adult brains — once you were grown, it was thought, all you could do was watch your brain cells die!
Adult neurogenesis (the creation of new brain cells in adult brains) was first discovered in 1965, but only recently has it been accepted as a general phenomenon that occurs in many species, including humans (1998).
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.
To choose a strategy, you must assess the situation. In this case, this may mean an evaluation of a written text. Let's look at how you might evaluate text.
We can classify text at one of three different levels, according to its structure and density1:
Find out about the pegword mnemonic
To celebrate Māori Language Week here in Aotearoa (New Zealand), I've put together a pegword set in te reo:
- tahi — ahi
- rua — ua
- toru — tūru
- whā — taniwha
- rima — rama
- ono — hono
- whitu — whatu
- waru — karu
- iwa — taraiwa
- tekau — rākau
Prevalence
Vascular dementia, as its name suggests, is caused by poor blood flow, produced by a single, localized stroke, or series of strokes.
It is the second most common dementia, accounting for perhaps 17% of dementias. It also co-occurs with Alzheimer's in 25-45% of cases. Although there are other types of dementia that also co-occur with Alzheimer's, mixed dementia generally refers to the co-occurrence of Alzheimer's and vascular dementia.
Speed-reading techniques
Like many memory improvement courses, speed-reading programs tend to make inflated claims. Also like memory programs, most speed-reading programs proffer the same advice. In essence, speed-reading techniques involve the following components:
Reading is a deceptive skill, for it is not a single process, but a number of processes. Thus, while you might be a fluent reader, in that you can swiftly and easily decode the letter-markings, and quickly access the meaning of the words, that doesn't mean you're a skilled reader of informational texts.
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.
In a 1987 experiment (1), readers were presented with a text that included one or other of these sentences:
or
Both texts went on to say: