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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).

Subliminal learning achieved notoriety back in 1957, when James Vicary claimed moviegoers could be induced to buy popcorn and Coca-Cola through the use of messages that flashed on the screen too quickly to be seen. The claim was later shown to be false, but though the idea that people can be brainwashed by the use of such techniques has been disproven (there was quite a bit of hysteria about the notion at the time), that doesn’t mean the idea of subliminal learning is crazy.

Alzheimer's disease currently affects one in 10 people over age 65 and nearly half of those over age 85.

More than 19 million Americans say they have a family member with the disease, and 37 million say they know somebody affected with Alzheimer's.

In the United States, the average lifetime cost per Alzheimer patient is US$174,000. (These figures are from the U.S. Alzheimer's Association).

Transfer refers to the ability to extend (transfer) learning from one situation to another. For example, knowing how to play the piano doesn’t (I assume) help you play the tuba, but presumably is a great help if you decide to take up the harpsichord or organ. Similarly, I’ve found my knowledge of Latin and French a great help in learning Spanish, but no help at all in learning Japanese.

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.

This is the last part in my series on understanding scientific text. In this part, as promised, I am going to talk about the difficulties novices have with scientific texts; what they or their teachers can do about it; and the problems with introductory textbooks.

Most cognitive processes decline with age

It does appear that most component processes of cognition decline with advanced age if the difficulty level is sufficiently high. For example, the following processes have all shown age effects:

I have previously reported on how gait and balance problems have been associated with white matter lesions, and walking speed and grip strength have been associated with dementia and stroke risk.

Learning a new language is made considerably more difficult if that language is written in an unfamiliar script. For some, indeed, that proves too massive a hurdle, and they give up the attempt.

I was listening on my walk today to an interview with Edward Tufte, the celebrated guru of data visualization. He said something I took particular note of, concerning the benefits of concentrating on what you’re seeing, without any other distractions, external or internal. He spoke of his experience of being out walking one day with a friend, in a natural environment, and what it was like to just sit down for some minutes, not talking, in a very quiet place, just looking at the scene.