Brain system behind general intelligence identified

Brain imaging while 11 individuals with traumatic brain injury and 15 healthy controls performed a working memory task has revealed that those with TBI showed greater connectivity between the hemispheres in the fronto-parietal regions (involved in working memory) and less organized flow of information from posterior to anterior parts.

The study used a new task, known as CapMan, which allows working memory capacity and the mental manipulation of information in working memory to be distinguished from each other.

A British study using data from 475,397 participants has shown that, on average, stronger people performed better across every test of brain functioning used. Tests looked at reaction speed, reasoning, visuospatial memory, prospective memory, and working memory (digit span). The relationship between muscular strength and brain function was consistently strong in both older and younger adults (those under 55 and those over), contradicting previous research showing it only in older adults.

I've reported before on the idea that the drop in working memory capacity commonly seen in old age is related to the equally typical increase in distractability. Studies of brain activity have also indicated that lower WMC is correlated with greater storage of distractor information. So those with higher WMC, it's thought, are better at filtering out distraction and focusing only on the pertinent information. Older adults may show a reduced WMC, therefore, because their ability to ignore distraction and irrelevancies has declined.

Why does that happen?

A small study that fitted 29 young adults (18-31) and 31 older adults (55-82) with a device that recorded steps taken and the vigor and speed with which they were made, has found that those older adults with a higher step rate performed better on memory tasks than those who were more sedentary. There was no such effect seen among the younger adults.

Musicians and people who are bilingual have long been shown to have a better working memory, and a new study makes a start on identifying why this might be so.

The brain imaging study, involving 41 young adults (aged 19-35), who were either monolingual non-musicians, monolingual musicians, or bilingual non-musicians, found that musicians and bilinguals needed fewer brain resources when remembering sounds.

This is just a preliminary study presented at a recent conference, so we can't give it too much weight, but the finding is consistent with what we know about working memory, and it is of some usefulness.

The study tested the ability of young-adult native English speakers to store spoken words in short-term memory. The English words were spoken either with a standard American accent or with a pronounced but still intelligible Korean accent. Every now and then, the listeners (all unfamiliar with a Korean accent) would be asked to recall the last three words they had heard.

When you're reading a picture book to a very young child, it's easy to think it's obvious what picture, or part of a picture, is being talked about. But you know what all the words mean. It's not so easy when some of the words are new to you, and the open pages have more than one picture. A recent study has looked at the effect on word learning of having one vs two illustrations on a 2-page open spread.