Thursday, September 20, 2012
When students study, they may monitor their progress during a study session by periodically forming judgments on how well they are remembering the material. Such judgments guide how much further study is deemed necessary. Researchers have studied this matter in the case of paired associate learning (where you learn lists of word pairs like dogs-cats, newspaper-book, etc.). In particular, researchers looked for correlations between later memory recall either immediately after learning or after a short delay in which judgments about learning are based on a covert attempt to recall. Results indicate that making judgments about how well something will be remembered can be just as efficient as taking an actual test.
In delayed judgments, the student typically makes an initial covert recall effort and then, based on that, judges how well the material was learned. Future recall tends to correlate with predictions on recall on a future test. That is not so surprising, other than the fact that other studies have shown students over-estimate what they have learned and under-estimate how much additional student would be beneficial.
A retrieval attempt directly reveals evidence of how well memory has formed. The act of retrieval itself may enhance learning. Successful retrieval could constitute an additional reinforcing learning opportunity. Indeed, other studies have shown that testing may lead to better final recall than a comparable amount of study. When an item is retrieved in covert recall and leads to a high judgment of learning, the item gets a long-term memory boost.
In the present study, the researchers directly compared final recall and delayed judgments of learning of paired association of lists of 40 words in Swedish (the native language of the subjects) and Swahili under differing testing conditions. One hundred twenty-one Swedish college students were divided into experimental groups: 1) repeated study and testing (study-test, “ST group”), 2) repeated study and termination of testing after the first successful recall test (study-test, dropout,“STd” group), and 3) repeated study and judgments of learning (study-judgment of learning “STjol” group).
Testing involved presenting the first word of a pair to serve as a cue to probe for recall of the associated word. All groups received four initial learning episodes with 5 seconds per item, after which they had 8 seconds to respond to test on the item (ST, STd) or render a judgment on their prediction of cued recall for that item a week later (STjol). All groups were compared for their performance on the same test a week later.
The ST group went through four successive study-test sessions, in each of which they studied all 40 word pairs on a computer screen. Immediately at the end of the list, the students took a 30-second distractor test (math quizzes). Then their recall was explicitly tested by presenting each Swahili word, whereupon they had 8 seconds to provide the Swedish equivalent. Students experienced four such study and test sessions. A similar procedure was used for the STd group, except that on any given test, each correctly recalled item was dropped from subsequent tests; thus the number of word pairs dropped from 40 on the first test to the number of pairs missed on the previous test.
The STjol group experienced a similar process including the 30 second distractor task, except that the test trials were replaced by jol trials. That is, instead of being required to provide the Swedish word that matched the Swahili probe word, the subjects were given 8 second to render a judgment for each word pair by answering this question: “How certain are you that you will recall the Swedish word in a week when we test you again? “ Students used a rating scale of 20% sure, 40%, 60%, 80%, 100%.
During the learning phase, the two ST groups increased their scores at about the same rate from the first session to the fourth. Thus, dropping a pair from testing once it was recalled correctly did not seem a disadvantage to learning. Authors assume the jol groups would have increased scores similarly, but of course they were not explicitly tested during the learning phase. Their prediction scores did, however, increase over the four sessions at a similar rate as recall did in the ST groups.
The key issue was elucidated on the memory test a week later. The ST group had better recall than the STd group, thus revealing that dropping items during study had long-term consequences. This is reminiscent of studies by others on flash cards that showed that best long-term recall was produced by re-testing with all cards in the deck, including those that were
answered correctly in a previous self-test.
The jol group performed better on the final test than the STd group but results were about the same as those for the ST group. Thus, making a delayed judgment during the learning phase about how well one has learned was just as effective for recall a week later as actually being tested during the learning phase.
What do we make of that? It seems that to make a prediction for ability to recall word pairs, a person has to first make a covert recall effort. If you covertly recall a word readily, you would like give a judgment rate of 100%, whereas if you struggled with covert recall, you might judge future recall at only 40%, for example. To make such judgments, the learner has to monitor the learning in real time. Such monitoring in order to render a judgment entails covert self-testing, which these results suggest is just as effective long term as explicit testing.
Such results confirm what we know about memory being promoted by self-testing, whether explicit or covert. As a practical matter for study strategies where it is inconvenient to take actual tests during study sessions, it prudent to conduct covert self-testing wherein a student asks questions like “how well have I remembered this item?” If the answer is “not well,” more study is called for. Confident judgments will tend to be confirmed when taking a real test later. In other words, making judgments about learning effectiveness during a learning phase helps a student to monitor progress and know how much time to devote to study. In addition, making such estimates seems, in itself, to promote learning because covert self-testing is required.
Jönsson, F. U., Hedner, M., and Olsson, M. J. (2012). The testing effect as a function of explicit testing of instructions and judgments of learning. Experimental Psychology. 59 (5): 251-257.
Monday, September 10, 2012
Deterioration of the brain usually sneaks up on us. By the time we realize it, it may be too late. As we get older, we more frequently start asking questions like “Where did I put the car keys?” “What was it I was supposed to get at the store?” “What’s your name again?” Most of us have had to ask questions like this, and it seems to happen more often as we get older. We can’t turn back our biological clock, but there are things seniors can do to reduce the rate of their mental decline. The time to act is while you are still relatively young.
As people age, beginning in early middle age, many of them experience a brain deterioration that progresses silently over the next decade or two, sometimes ending in devastating senility. Behaviorally, aging can cause your reflexes to slow. You walk and act slower. You even talk slower. Our memory starts to fail, especially the short-term form of memory ability that is so crucial for learning new things.
Now that bran-scan technology is widely available, physicians have discovered that the brain usually shrinks as people get older. The shrinkage increases the space between the brain surface and the skull. The cavities that hold cerebrospinal fluid get bigger. Nerve tracts in the brain shrivel, even leaving gaping holes in the brain. The “dendritic trees” shrivel, and these have major consequences because dendrites are the parts of neurons that form the contact points, and their loss reduces brain circuitry. You may also lose 40% or more of your dopamine neurons, and that may lead to Parkinson’s disease
For aging individuals, the challenge is to reduce the rate of their decline. This has created a growth anti-aging industry focused on vitamins and supplements, fad diets, gym facilities, mind training programs. The good news is that some of these things work, if they are begun while people are in early middle age. Given that our country now has so many baby boomers in the over-50 category, it seems useful to summarize some things people can do to prevent or slow memory decline as they age. I particularly like the summary at this site.
Here is an expanded list of things I think are especially important for people entering middle age.
1. Get better organized. Many things we try to remember do not have to be remembered if we get better organized. Car keys, for example, should ONLY be in the car, your pocket/purse, or the same place in your house. Ditto for many other objects, such as purse, hat, glasses, etc. Life is a lot simpler when you have a place for everything, with everything in its place. Habit relieves the memory.
2. Make a special effort to pay attention, concentrate. Research shows that aging reduces a person’s ability to focus and pay attention. This also means that seniors have to work harder at filtering distractions, such as when we open the refrigerator door and forget what we are looking for because we thought of something else before we opened the door. New learning has to be consolidated to form lasting memory, and this takes a little uninterrupted time and conscious rehearsal right after you learn it. Seniors are especially susceptible to having temporary memories wiped out by distractions.
3. Challenge yourself mentally. Seek out new experiences, an active social life, and mental demands such as learning a new language, playing chess, or getting an advanced college degree. Learning new things always has the benefit of making you feel good about yourself, and this is especially true for seniors who accomplish things most people think they can’t do. By the way, there is abundant research literature showing that a lifetime of vigorous learning helps stave off Alzheimer’s disease.
4. Reduce Stress. Acute stress helps you be alert, pay attention better, and increase your chances of remembering what is happening at the time of stress. But chronic stress, whether caused by the same or different stressors, clearly disrupts memory formation and recall. Chronic stress and the hormones it releases can actually kill neurons and shrink the brain (which shrinks with age anyway, and only gets worse with chronic stress).
5. Eat foods with vitamins and anti-oxidants. Make certain you have a balanced diet. Supplements usually won’t help memory unless you have a nutritional deficiency. But even with a good died, adding vitamins C, D, and E can be helpful. Several research studies indicate a memory benefit from eating foods loaded with anti-oxidants. Blueberries (especially on an empty stomach). Another potent anti-oxidant is an ingredient in red wine, resveratrol, but there is no way you could drink enough; however, resveratrol supplements are now on the market. There is also suggestive evidence for memory improvement from omega-3 fatty acids and folic acid. Pharmaceuticals to improve memory are in the works, but you may have to wait quite a while before research shows which ones really work.
6. Don’t get obese, especially in middle age.
Confocal microscopy reveals that every added pound of fat adds approximately one mile of capillary tubing. Obviously, all these added vascular tubing puts a strain on the heart. A diet that produces new fat may well contribute to hardening of the arteries, which in turn compounds the added workload on the heart. People who are obese commonly have high blood pressure and other risk factors involving metabolism.
Obesity is a common cause of diabetes, which adds its own toll on blood vessels and the heart, as well as on nerve cells. No wonder then that obese people may develop mental deterioration. The problem may be worse in women. The more a woman weighs, the worse her memory. No, I am not a chauvinist pig. This claim comes from actual research —by a woman, no less. Diana Kerwin and her colleagues at Northwestern University studied 8,745 ages 65 to 79 and found that for every one-point increase in body mass index, the score on a 100 point memory test dropped by one point.
A likely cause of mental decline in most people is diminished blow flow in small vessels that are easily plugged by cholesterol and lipids or ruptured by high blood pressure. These “mini-strokes” are probably quite common as we age, and though they go undetected, they cause a cumulative damage which progressively affects our behavioral and mental capabilities. Brain cells are among the most metabolically active of all cells: they constantly fire electrical pulses and secrete relatively huge amounts of secretions (neurotransmitters). The brain consumes about 20% of all the body’s oxygen, even though it only ways about 3.5 pounds.
When brain cells do die or are damaged for any reason, healthy neurons are assaulted by inflammatory chemicals, like cytokines, that are released by the brain’s immune cell system. Fat deposits not only stress the heart, they also increase the amount of cytokines, which are hormones that can cause inflammation. Brain inflammation is also commonly caused by infections such as colds and flu and by diets deficient in anti-oxidants.
7. Exercise the body. Though exercise doesn’t do much to cause weight loss unless you are a marathon runner of tennis singles champion, it has many other benefits (improved circulation of blood to the brain, improved levels of HDL cholesterol) that can directly benefit memory and cognitive function. Vigorous aerobic exercise can improve your circulation and perhaps blood flow in the brain. But there also seem to be memory benefits from exercise that is independent of blood circulation. We don’t know why. Maybe relief of stress and improved mood are factors. We know that positive emotions help memory, but for unknown reasons.
8. Exercise the memory. The more you make an effort to memorize, the easier it seems to get. Practice the memorization tricks used by “memory athletes” that I describe in my book. I describe in my book specific image-based systems (“peg systems”) for performing astonishing memory feats, such as card counting, remembering long strings of numbers, and remembering the gist of what is on every page of a magazine or book.
9. Get plenty of sleep. Many studies show the brain is processing the day’s events while you sleep and consolidating them in memory. This kind of “off-line” rehearsal occurs just for the learning experiences on the day of sleep. Naps help too! How’s that for good news?
10. Believe in your brain’s ability to get better. Of course genes and luck have a lot to do with how well one ages mentally. But genes and luck seem to be more common in people who do the nine things mention above. Too many seniors buy into the popular myth that old dogs can’t learn new tricks. They resign themselves to defeatism. But the bottom line is that, unless you have Alzheimer’s disease, you can improve your mental sharpness. Getting older has enough frustrations. Don’t compound them by tolerating mental decline. Enjoy an improved brain.