Monday, October 21, 2013
In 1913, Ebbinghaus demonstrated that spacing learning out over time creates much more efficient learning than cramming a learning task into a single intense session. Now, a new discovery has been made for a specific spaced-learning strategy that so far is the best of all. In reviewing this new design, Kelley and Whatson (2013) point out experiments showing that this kind of spaced learning is optimal for information encoding and for activation of the genes needed to form long-term memory.
And what is the design? The idea begins with the established notion that a given learning task should be “chunked” so that it can be studied in a short time, on the order say of 20 minutes. What is novel about the new design is that a given chunk is studied three times in a single session, with two intervening “rest” periods of 10 minutes in which there is little mental activity. During the rest periods, physical activity, like shooting hoops or cycling, seem to be ideal. The reason for these intervening rest periods is that thinking about new information or performing mental tasks creates interference with the memory-forming processes already under way.
Of course, like most learning tasks, a single session, even with three repetitions within it, is not likely to be sufficient unless you are really adept at mnemonic techniques (Klemm, 2012). After a day or so, this strategy needs to be repeated one or more times.
This is so simple to do and, if replicated in more studies, should become standard practice in schools. However, very few teachers know about this technique and school curricula are not designed to be taught this way. Changing the educational establishment is probably too much to hope for. But this strategy can be used by all students in homework study. Home schoolers and students taking Internet courses can easily use the technique on their own.
If you try this approach, please add comments to this post to let us know how it works for you.
Kelley, P. and Whatson, T. (2013). Making long-term memories in minutes: a spaced learning pattern from memory research in education. Frontiers in Human Neuroscience. 25 September. Doi: 10.3389/fnhum.2013.00589.
Klemm, W. R. (2012). Memory Power 101. New York: Skyhorse Publishing.
Sunday, October 13, 2013
“Life, liberty, and the pursuit of happiness:” some people might argue that the U.S. Constitution endorses hedonism, and indeed many politicians want to ignore or get rid of the Constitution, but not necessarily because of hedonism. We should not be dismissive about encouraging people to pursue happiness. Happiness can be good for your brain. Depression is surely bad for your brain.
Positive mood states promote more effective thinking and problem solving. A recent scholarly report reviews the literature demonstrating that positive mood broadens the scope of attentiveness, enhances semantic associations over a wide range, improves task shifting, and improves problem-solving capability. The review also documents the changes in brain activation patterns induced by positive mood in subjects while solving problems. Especially important is the dopamine signaling in the prefrontal cortex.
Published studies reveal that a variety of techniques are used to momentarily manipulate mood. These have included making subjects temporarily happy or sad by asking subjects to recall emotionally corresponding past experiences or to view film clips or hear words that trigger happy or sad feelings,
The effect of happiness on broadened attentiveness arises because the brain has better cognitive flexibility and executive control, which in turn makes it easier to be more flexible and creative. Happy problem solvers are better able to select and act upon useful solutions that otherwise never consciously surface. Happiness reduces perseverative tendencies for errant problem-solving strategies. The broadened attentiveness, for example, allows people to attend to more stimuli, both in external visual space and in internal semantic space, which in turn enables more holistic processing. For example, in one cited study, experimenters manipulated subjects’ momentary mood and then measured performance on a task involving matching of visual objects based on their global versus local shapes. Happy moods yielded better global matching.
Other experiments report broader word association performance when subjects are manipulated to be happier. For example, subjects in a neutral mood would typically regard the word “pen” as a writing tool and would associate it with words like pencil or paper. But positive mood subjects would think also of pen as an enclosure and associate it with words like barn or pigs. This effect has been demonstrated with practical effect in physicians, who, when in a happy mood, thought of more disease possibilities in making a differential diagnosis.
The review authors reported their own experiment on beneficial happy mood effects on insightfulness, using a task in which subjects were given three words and asked to think of a fourth word that could be combined into a compound word or phrase. For example, an insightful response to “tooth, potato, and heart” might be “sweet tooth, sweet potato, and sweetheart.” Generating such insight typically requires one to suppress dominant “knee jerk” responses such as associating tooth with pain and recognizing that pain does not fit potato while at the same time becoming capable of switching to non-dominant alternatives.
Other cited experiments showed that happy mood improved performance on “Duncker’s candle task.” Here, subjects are given a box of tacks, a candle, and a book of matches, and are asked to attach a candle to the wall in a way that will burn without dripping wax on the floor. Subjects in a happy mood were more able to realize that the box could be a platform for the candle when the box is tacked to the wall.
Such effects of happy moods seem to arise from increased neural activity in the prefrontal cortex and cingulate cortex, areas that numerous prior studies have demonstrated as crucial parts of the brain’s executive control network. Similar effects have been observed in EEG studies. Other research suggests that the happiness effect is mediated by increased release of dopamine in the cortex that serves to up-regulate executive control.
The review authors described a meta-analysis of 49 positive-psychology manipulation studies showing that momentary happiness is readily manipulated by such strategies as deliberate optimistic thinking, increased attention to and memory of happy experiences, practicing mindfulness and acceptance, and increasing socialization. The effect occurs in most normal people and even in people with depression, anxiety, and schizophrenia. Biofeedback training, where subjects monitor their own fMRI scans or EEGs, might be an even more effective way for people to train themselves to be happier.
The main point is that people can be as happy as they choose to be.
For more on how positive mood influences memory ability,
see my new book, Memory Power 101 (http://skyhorsepublishing.com).
 Subramaniam, K. and Vinogradov, S. (2013). Improving the neural mechanisms of cognition through the pursuit of happiness. Frontiers in Human Neuroscience. 7 August. Doi: 10.3389/fnhum.2013.00452
Friday, October 04, 2013
In other blog posts I have explained why sleep is good for the brain in general and memory formation in particular. Now a new discovery provides another reason for people to get enough sleep. The study examined a type of support cell in the brain, oligodendrocytes–let’s call them oligos for short. These cells wrap their membranes around nerve cells to form what is called myelin, which forms an electrical insulation in a way that speeds up the propagation of nerve impulses through neural networks. You may have heard about oligos in reading about multiple sclerosis, a disease that impairs nerve communication because oligos die and the myelin insulation degrades.
Speed of transmission is important–it influences IQ for example. As you know from buying a new computer, the faster processor speed gives it new capabilities your old clunker could not do. A similar idea applies to the brain.
Anyway, this new study, from the University of Wisconsin, focused on oligos because other research had shown that sleep promoted the expression of several genes that are involved in synthesis of cell membranes in general and those in oligos in particular. Unlike neurons, oligos die, and are replaced in the brain. Thus, anything that affects their turnover is important for brain function. Sleep has been implicated in this turnover because a common neurotransmitter in the brain, glutamate, is known to increase in wakefulness and decline during sleep. Glutamate suppresses maturation of oligo precursor cells into formation of myelin insulation.
In this particular study, investigators examined a genome-wide profile of oligo gene expression in mice after a 6-7 hour periods of sleep or spontaneous wakefulness, or four hours of forced wakefulness (sleep deprivation). They found that 357 genes were expressed differently, depending on the time of day, in response to normal daily rhythms. More dramatic was the observation that 714 genes changed expression in conjunction with the sleep/wakefulness cycle, independent of the time of day. Of these genes, 310 were “sleep” genes that were selectively activated during sleep.
Many of the sleep genes contribute to maturation of oligos into myelin. In follow up experiments, mice were injected with a radiolabeled tag that marks the birth of new cells. Injection occurred eight hours before mice spent a long period of either of wakefulness or sleep. The number of newly born oligos was almost double in the sleep group compared to the wake group. More detailed analysis showed that this increase was specifically correlated with the amount of REM sleep (dream sleep in humans).
This REM effect may have particular importance in humans. Most REM sleep occurs in the early morning hours and only after substantial time has been spent in non-REM stages of sleep. Thus, cutting a night’s sleep short by getting up early may decrease the amount of REM time and thus the beneficial effects on oligo proliferation. So don’t feel guilty about “sleeping in” from time to time.
We might also think about how these findings could have special relevance to children, whose brains are incompletely myelinated. Getting children up early in the morning to start school at 8 AM may not be such a good idea. Until school districts get around to changing school hours, you might tell you kids about my learning and memory improvement e-book, Better Grades, Less Effort, available at Smashwords.com.
Bellesi, M., et al. (2013) Effects of sleep and wake on oligodendrocytes and their precursors. J. Neuroscience. 33 (36), 14288-14300.