Articles
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).
We all like simple solutions. However much we may believe we are ‘above’ black-&-white dichotomies, that of course we understand that every situation is complex, nevertheless we have a brain that can only think of a very very few things at once. So it's unsurprising that we are drawn to solutions that can be summed up simply, that can fit comfortably within the limitations of working memory.
I’ve recently had a couple of thoughts about flow — that mental state when you lose all sense of time and whatever you’re doing (work, sport, art, whatever) seems to flow with almost magical ease. I’ve mentioned flow a couple of times more or less in passing, but today I want to have a deeper look, because learning (and perhaps especially that rewiring I was talking about in my last post) is most easily achieved if we can achieve "flow" (also known as being ‘in the zone’).
Let’s start with some background.
What do we mean by word-finding problems?
Here are some examples:
- increasing use of circumlocutions rather than specific terms (e.g., "I wonder where the thing that goes here is")
- use of empty phrases, indefinite terms, and pronouns without antecedents (i.e., referring to something or someone as "it" or "him / her" without first identifying them by name)
- increased frequency of pauses
These problems are all characteristic of Alzheimer's, but also, to a much lesser extent, of normal aging.
A New Yorker cartoon has a man telling his glum wife, “Of course I care about how you imagined I thought you perceived I wanted you to feel.” There are a number of reasons you might find that funny, but the point here is that it is very difficult to follow all the layers. This is a sentence in which mental attributions are made to the 6th level, and this is just about impossible for us to follow without writing it down and/or breaking it down into chunks.
Let’s talk about the cognitive benefits of learning and using another language.
In a recent news report, I talked about the finding that intensive learning of a very novel language significantly grew several brain regions, of which two were positively associated with language proficiency. These regions were the right hippocampus and the left superior temporal gyrus. Growth of the first of these probably reflects the learning of a great many new words, and the second may reflect heavy use of the phonological loop (a part of working memory).
Two large-scale international studies have become established to compare countries' performance in the core subjects of literacy, mathematics and science.
TIMSS: Trends in International Mathematics and Science Study
TIMSS is an international study involving 50 countries that assesses math and science achievement at four year intervals. It has been running since 1995. Students are assessed in the 4th and 8th years of school, and in their final year. The next assessment round will be in 2007.
You may have heard of “g”. It’s the closest we’ve come to that elusive attribute known as “intelligence”, but it is in fact a psychometric construct, that is, we surmise its presence from the way in which scores on various cognitive tests positively correlate.
In other words, we don’t really know what it is (hence the fact it is called “g”, rather than something more intelligible), and in fact, it is wrong to think of it as a thing. What it is, is a manifestation of some property or properties of the brain — and we don’t know what these are.
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.