Evidence Matters

Evidence Matters

Quite often, I suspect, readers of my memory columns wonder (complain?) about my emphasis on memory studies, what they show and do not show. Editors and publishers have told me that readers do not want to read about the evidence behind my advice. “Do this, don’t do that” is the kind of thing they want me to say. I, after all, am the authority and readers expect to take my word for it. However, I am constitutionally reluctant to pose as a know-it-all, and more so am opposed to believing that people don’t benefit from introspection about what they are doing and why they don’t change to become better at learning and memory.

A more practical reason is that improving learning and memory ability requires breaking old habits and the imposing difficulty of forging new and better approaches and mental habits. Just telling people what they should do (because I and fellow scientists know best) is not likely to be very effective. Change does not come easy to anybody and is even more difficult if clear and good reasons are not provided for making the change.

For example, in my e-book Better Grades, Less Effort (available at Amazon for Kindle and at Smashwords.com for all other readers), I tell students not to cram for exams. But that advice is largely ignored if I don’t explain why cramming is inefficient and unreliable. I have to be convincing, and that requires presenting the evidence for my position. Cramming is something students naturally do. It is not easy to get students to stop procrastinating and discipline themselves into routine study protocols.

There is also this: knowledge is often partial and temporary. What we think is the best way to go about things may even be wrong or sub-optimal at best. If we don’t know the evidence for the various options, how can we make the best choice?

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How Memory Is Stored

When you look up a phone number, the digits are coded as patterns of nerve impulses flowing around in a group of neurons. As long as the encoded numbers are “on-line” like this, your memory has access to the numbers.

But what if you start thinking about something else before you dial? Those neurons now have been recruited for another purpose and no longer carry the original number encoding. So you have to look up the number again.

But if the on-line activity goes on long enough, your memory of the number encoding can become stored permanently. How does that happen? Evidence indicates that new learning, as it becomes stored permanently causes new junctions (synapses) to be formed in the neurons of the circuit that originally encoded the information. You can even see physical signs in the form of new growths, called spines, on the nerve fiber terminals.

But what creates these new spines and their functional connections? This involves new RNA and protein synthesis. This in turn requires some genes to be activated to manufacture and maintain the new spines. There are apparently memory genes that are activated by nerve impulse activity. Gene activation is typically driven by specific regulatory proteins, and one such activity-dependent regulatory protein is called CREB.

For a short UTube video on gene expression, click here.

Formation of long-term memory first requires nerve impulse activation of the compound, cyclic AMP. The early studies on CREB were done in different labs, one of which used the mollusc, Aplysia, and the other using the fruit fly. So what does activated AMP do? One of the things is that it binds to a pre-existing protein (called protein kinase), causing part of the protein’s subunits to be liberated. The liberated components move to the neuron’s nucleus, where they bind to another protein, called CREB. Activated CREB then binds to the memory genes, switching them on.

Most recently, another activity-dependent memory gene activator has been discovered called Npas4. This one is especially important because it exists in mammals (mice were the experimental animal) and because it occurs in the hippocampus, the part of the brain necessary to form explicit long-term memories. Moreover, this protein regulates many well-known activity-regulated genes, which suggests that Npas4 might be a “master” control protein. In the study, Npas4 emerged in response to a contextual learning task. A knock-out gene strain of mice that had no Npas4 were poor at learning this task, and the deficit was restored by reversing the Npas4 knockout.

Research on drugs affecting activity-dependent gene regulator proteins is exciting, and may lead to a memory pill. In the meanwhile, the best you can do for your memory is to provide learning situations where original encoding is preserved intact long enough for these gene activation processes to be accomplished.

Sources:

1. Kandel, Eric R. (2005), "The Molecular Biology of Memory Storage: A Dialog Between Genes and Synapses", Bioscience Reports 24 (4–5): 475–522, doi:10.1007/s10540-005-2742-7, PMID 16134023

2. Ramamoorthi, K. et al. (2011). Npas4 regulates a transcriptional program in CA3 required for contextual memory formation. Science. 334: 1669-1675.

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To Cram or Not to Cram? -- That Is the Question

Most students, at one time or another, have crammed for an examination. Researchers refer to this as massed trials, where objects of learning are studied all at the same time in one session. Students may be forced to cram because they have procrastinated or did not have a regular, organized, and disciplined approach to study. Non-students may cram too, as in lawyers briefing a case, speakers rehearsing a speech, professors preparing a lecture, salesmen practicing a pitch, and so on.

In most situations research has made it abundantly clear that spacing the learning over many shorter sessions is much more effective than trying to do it all in one big session. Surprisingly, longer intervals between learning sessions are more effective than shorter intervals. For example, one study of students learning foreign-language words found that recall was highest at 56-day intervals as opposed to 28-day or 14-day intervals. The total amount of study time was cut in half: 13 sessions spaced 56 days apart produced comparable recall as 26 sessions with a 14-day interval.

Unfortunately, most academic courses are not designed to support longer study intervals (perhaps educators need to re-think how things are done). Not enough studies have been performed to examine which spacing protocol works best for certain kinds of learning tasks, but it is clear that massed trials are not efficient.

Why spacing makes such a big difference is not understood either, but it does have to do with basic biology. A recent study on seal snails, of all things, showed that the gene expression underlying long-term memory was affected by how five training shocks were spread out over time. Compared with a control test where snails got five shocks at 20-minute intervals, the most effective pattern (developed by computer model) was to give three shocks at 10-minute intervals, followed by a fourth at five minutes later and the fifth shock 30-minutes later.

There is no reason to think this protocol is optimal for humans learning a variety of tasks. But it does help make the point that spaced learning is more effective and perhaps irregular intervals might be better than evenly spaced ones.

Why does spacing work? Two ideas prevail. One is that in massed trials, there is not much time for each presentation to be processed in context. In spaced trials, each learning presentation occurs in a slightly different context, thus providing many more implicit cues that can be unconsciously accessed during retrieval attempts.

Finally, a host of recently reported studies show that each time you are re-exposed to a learning object, the memory is re-consolidated. Successive consolidation events reinforce each other. Multiple consolidations do not occur in massed trials because consolidation takes many minutes or even hours.

Given what I have explained elsewhere on the benefits of self-testing, I suspect that spaced learning would be optimized if the learner self-tested first during each rehearsal session and then checked the recall against the original learning material.

Sources:

Bahrick, H. P. et al. (1993). Maintenance of foreign language vocabulary and the spacing effect. Psychological Science. 4 (5): 316-321.

Zhang, Y. et al. (2011). Computational design of enhanced learning protocols. Nature Neuroscience. Published online Dec. 28, doi: 10.1038/nn.2990

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Neat summary graphic on memory

One of the followers of this blog called my attention to a neat summary graphic on memory that her group at Online Colleges has posted. See http://www.onlinecolleges.net/2012/01/09/memory-works/ I think it is a good summary and consistent with what I have been published in my books (http://thankyoubrain.com) and this blog.

... nice job.

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Improving Memory Involves More Than Gimmicks

Two elderly couples were enjoying friendly conversation when one of the men asked the other, "Fred, how was the memory clinic you went to last month?"

"Outstanding," Fred replied. "They taught us all the latest psychological techniques - visualization, association - it made a huge difference for me."

"That's great! What was the name of the clinic?"

Fred went blank. He thought and thought, but couldn't remember. Then Fred smiled and asked, "What do you call that red flower with the long stem and thorns?"

"You mean a rose?"

"Yes, that's it!" He turned to his wife. . ."Rose, what was the name of that clinic?"

Memory techniques, like visualized associations, are important for improving memory. I sometimes get chided, as in a recent commentary, for writing about things that readers think are unrelated to memory.

But memory is not independent of everything else that brains do. This includes general thinking abilities, motivation, attitudes, lifestyle, and the mental challenges that a person seeks. General health, exercise, sleep, response to stress, and diet are also important. I have elaborated on these influences on memory in my books and learning and memory blog. Research continually expands our understanding of these indirect influences on learning and memory, and I try to keep readers informed of the practical applications of these developments.

Another under-appreciated area about memory is the role of learning. As two sides of the same coin, learning and memory are interdependent. How we approach a learning task has enormous impact on how much of it we remember. These factors include study strategy, attentiveness, distractibility and cognitive interference, and organization and categorization of learning material. Likewise, how much you remember of learned material affects one’s capacity for understanding and memorizing new material. Experts in a given field have become experts because what they have memorized includes learning templates and schema that help them to be better learners than non-experts. They may have learned to increase working memory capacity, which in turn improves the ability to think and solve problems.  That is, the more they know, the more they can know.

Memory ability is multi-dimensional. The complete learner employs all the means of improving knowledge.

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Your Kid May Be Smart. Just Don’t Tell Him So Too Often

Some people say that we learn best from our mistakes. But all of us know about people who never seem to learn from their mistakes. This failure to learn is most obvious with people who keep making poor decisions and lifestyle choices. The psychological explanations are many and complex.

For simplicity, let us restrict explanation to the world of education. Educational philosophy has changed a great deal in the 50 years since I was in school. Back then, for example, I had the highest grades in school, but many of my teachers went out of their way to cut me down a notch or two so I wouldn’t get conceited. Aside from the debatable question of whether that worked, the point is that today, the educational establishment has the opposite philosophy. They tend to tell all kids they are smart. I have seen elementary schools where most students are selected as “Honors Students.” I know college education professors who won’t give anything less than an A.  Why is praise so liberally applied? In part, the idea is to bolster student self-esteem. Also motivating teachers is the reluctance to admit that some kids are smarter than others. Equal outcome is the politically correct expectation. That’s why we have the No Child Left Behind law. Everybody is supposed to succeed because all are presumed equal. Of course the reality is that this is a lie, and the only way everybody achieves the same is to lower the standards to the least common denominator.

Research clearly shows that whether students learn best from their mistakes depends on a student’s self-perception. Research by Carol Dweck and colleagues at Stanford demonstrated that the students who are most likely to learn from their mistakes are those who don’t think of themselves as smart as such but smart enough to get smarter. They have a “growth mindset,” a belief system that they can get better if they will just invest the time and effort. In one of the group’s experiments, half of the students were repeatedly praised for “being smart,” and these students were not good at learning from mistakes. It is not clear why. Maybe they thought the problem was in the learning material, not in them. The other half of students were praised for effort and improvement and these students got better and made fewer mistakes. Several months later, all students repeated a standardized test, and the “smart” students’ scores dropped 20%, while the “growth mindset” students scored 30% higher.

Jason Moser followed up this idea with an experiment in which subjects performed a tedious task in which some mistakes were inevitable. Those who did best at learning from the mistakes were those who believed most strongly that they could get better at this task and make fewer mistakes. Brain electrical recordings during the task revealed two electrical signatures of the mindset, the first being an error-related negative voltage about 50 milliseconds after an error occurred, and a second positive voltage up to about a half a second later. The size of this second signal correlated with how intensely the subject paid conscious attention and was distressed by the mistake. This second signal was larger in those subjects that were the best learners, and they made even fewer mistakes as the task was repeated.

Ego is probably a factor. The “smart” students may seem to have plenty of self-esteem, but apparently failure is too painful a challenge to their ego and they find ways to rationalize or dismiss the mistakes. Students with a growth mindset may have better self-esteem, because they accept the challenge to their ego, and believe they can get better, which usually becomes a self-fulfilling prophecy.

A little humility is a good thing. Most of us, even the smartest, have a lot to be humble about. There is even a book on the subject, “Why Do Smart People Make Such Stupid Mistakes.”

Sources:

1. http://www.brainology.us/default.aspx?gclid=CNn04-q_oq0CFbEDtgodQj4iuQ

2. Mangels, J. A. (2006) Why do beliefs about intelligence influence learning success? A social cognitive neuroscience model. SCAN, 1, 75–86. doi:10.1093/scan/nsl013

3. Merrington, C. (2011). Why Do Smart People Make Such Stupid Mistakes, St Albans, Herts, United Kingdom: Ecademy Press.

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My other blog activities

I am delighted to have so many followers. However, it is not nearly as many as I apparently have at Psychology Today, where the reader views of my posts there now total over 65,000 (see http://www.psychologytoday.com/blog/memory-medic). Some of my posts there are cross posts from this blog, but others are unique.

You may want to know about my other blog on excuse-making, misplaced blame, and how to grow in competence and self-esteem by dealing with deception of self and others. See http://blamegameblog.blogspot.com.

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