More Bad News for Multi-tasking

Memory formation is often prevented when one event follows too soon after an initial learning event. It is also true that memory of initial learning events can be blocked if you try to learn two things at once. In fact, learning may be disrupted for both things.

In a recent test of this phenomenon, a group of 29 people (17 to 30 years of age) was trained to discriminate two sound pips that differed in length by a fraction of a second. In one group of subjects, the training occurred consecutively, which ordinarily produces some inefficiency with learning because the second task interferes with remembering the first. In this study, some learning did occur, in spite of the sequential tasks. However, results from another group of subjects revealed that when practice on the two tasks was interleaved, there was no learning on either condition.

This indicates that acquistion (initial learning) is vulnerable to multi-tasking, perhaps even more so than when learning of one task is followed too soon by another learning task. In other words, multi-tasking can interfere with initial learning, just as it does with formation of memory.

Source: Banai, K. et al. 2010. Learning two things at once: differential constraints on the acquisition and consolidation of perceptual learning. Neuroscience. 165: 436-444.

More Evidence that Naps Help Memory

I have mentioned before the value of naps for improving the formation of memories. Another recent student confirms this conclusion. Matthew Walker and colleagues an the University of California at Berkeley divided 39 young adults into two groups. At noon, all the participants took part in a memory exercise that required them to remember faces and link them with names. Then the researchers took part in another memory exercise at 6 p.m., after 20 had napped for 100 minutes during the break.

Those who remained awake performed about 10 percent worse on the tests than those who napped, Walker said. Students take note: 10% can be the difference between an A and a B.

Source: Walker, Mathew. 2010. Current Models of Mechanisms of Sleep-Dependent Memory Presentation at the annual meeting of the American Association for the Advancement of Science meeting, San Diego, Feb. 21.

More on the Benefits of Blueberries

In several earlier posts, I discussed experiments that indicate blueberries can improve memory. There is a more recent study in 9 older adults (average age was 76) who were showing early signs of deterioration in memory capability. For 12 weeks, the subjects were given daily doses approximately 2.5 cups (exact amount adjusted according to body weight) of juice made from commercially available frozen wild blueberries. Berries were thawed, pressed, filtered, pasteurized, and then bottled. A comparison group drank the same amount of fake blueberry juice.

The subjects were instructed to refrigerate the juice at home and to take prescribed daily quantities in equal, divided dosages with the morning, midday, and evening meals. Memory tests (word-pair association, word list) were given before and after the test period. Significant gains in memory ability were seen in the blueberry group. Scores on both kinds of memory tests increased about 33%.

Additionally, there was suggestive evidence that blueberry juice reduced signs of depression and lowered blood glucose levels. This needs to be pursued in future research.

In an earlier post I had summarized a study that showed that milk protein interfered with the blueberry effect. Presumably other proteins could also interfere. In other words, I am suggesting that even better results might be obtained if the juice is taken on an empty stomach (assuming of course that this does not cause upset stomach).

The beneficial effects of the blueberries are thought to be linked to their flavonoid content - in particular anthocyanins and flavanols. The exact way in which flavonoids affect the brain are unknown, but they have previously been shown to cross the blood brain barrier after dietary intake.

Source:
Krikorian, R. et al. (2010) Blueberry supplementation improves memory in older adults. J. Agricultural and Food Chemistry. doi: 10.1021/jf9029332