Monday, October 28, 2013

Learning how to learn

Some study techniques accelerate learning, whereas others are just a waste of time – but which ones are which? Scientific American Mind magazine reviewed more than 700 scientific articles on 10 commonly used learning techniques. And this is what they found.

Most students report rereading and highlighting, yet these techniques do not boost performance, and they distract students from more productive strategies. Underlining, highlighting or otherwise marking material is simple and quick – but it does little to improve performance. In fact, it may actually hurt performance on some higher-level tasks. It may be that underlining draws attention to individual items rather than to connections across items. 84 % of the students said they reread textbooks or notes during study. It requires no training, makes modest demands on time, and shows some benefits on recall and fill-in-the-blank-style tests. Yet the evidence is muddy that rereading strengthens comprehension. Most of the benefit of rereading appears to accrue from the second reading, with diminishing returns from additional repetitions. Don’t waste your time! In head-to-head comparisons, rereading fares poorly against more active strategies. But which are these?


There are two clear winners: self-testing and distributed practice. How it works. Unlike a test that evaluates knowledge, practice tests are done by students on their own, outside the class. Methods might include using flash cards to test recall or answering the sample questions at the end of a textbook chapter. Although most students prefer to take as few tests as possible, hundreds of experiments show that self-testing improves learning and retention. This technique seems to trigger a mental search of long-term memory that activates related information, forming multiple memory pathways that make the information easier to access. Regarding the second technique, distributed practice, this is how it works. Students often “mass” their study. But distributed learning over time is much more effective. Longer intervals are generally more effective. 30-day delay improves performance more than lags of just one day. To remember something for one week, learning episodes should be 12 to 24 hours apart; to remember something for five years, the material should be spaced 6 to 12 months apart. Although it may not seem like it, you actually do retain information even during these long intervals, and you quickly relearn what you have forgotten. Long delays between study periods are ideal to retain fundamental concepts that form the basis for advanced knowledge.

The techniques presented above are proved to be the most practical. Along with them, there are a few with moderate utility. Elaborative interrogation requires to put yourself in the position to ask “Why?”. “Why does it make sense that ….?” or “Why is this true?”. This is effective especially if you already know something about the subject.  Another technique is self-explanation. In this case, students generate explanations of what they learn, reviewing their mental processing with questions such as “What new information does the sentence provide for me?”. Similar with elaborative interrogation, self-explanation may help integrate new information with prior knowledge. It helps in solving math problems, logical reasoning puzzles and learning from narrative texts. At the bottom of my list is interleaved practice. In this technique students alternate a variety of types of information or problems, instead of study in blocks, finishing one topic before moving on to the next. It improves performance on algebra problems and is effective to train medical students to put correct the diagnostic. But this technique is useful for those who are already reasonably competent.

Why don’t students use more effective study techniques? The research done by Scientific American Mind magazine found some explanations. It seems they are not being taught the best strategies, perhaps because teachers themselves are not schooled in them. A second problem may be that in the educational system, the emphasis is on teaching students content and maybe some critical-thinking skills. Less time is spent on teaching them how to learn. The result can be that students who do well in their early years, when learning is closely supervised, may once struggle once they are expected to regulate their own learning in high school or college.

Monday, October 21, 2013

Our genome as a memory stick

We tend to see humans as a combination of nature and nurture, nature being represented by the genes we inherit from parents and nurture by the impact of environment. But the reality is far more complex and subtle. What if the genes are only a biological data base especially built for saving the relevant changes from the environment we live?


 For people who are more or less familiar with psychology there is a well-known theory that intelligence is classified into two main categories: fluid and crystallized. Fluid intelligence is thought to deal with solving new problems, while crystallized intelligence is a sort of reservoir of knowledge. And the later are thought to be developed through the investment of fluid intelligence (hence the name “investment theory of intelligence”). But a new  study made by Dutch scientists from Tilburg and Amsterdam universities contested this view. In striking contrast with the general view that fluid intelligence would have a heavy genetic base while the crystallized one would be based on learnt knowledge or cultural load rather than genes, this new study found the exact opposite. Using an IQ test which has both culture free and culture loaded items, they found that highly culturally items had higher heritability coefficients (hence a stronger genetic component) and were also highly related to general IQ score. How to interpret these findings? The authors advanced the theory that people with more complex minds tend to seek out intellectually demanding environments, and as they develop higher levels of cognitive ability, they will be more favored to achieve higher levels of knowledge. So cognitive abilities and knowledge dynamically feed off each other. This is similar with studies which tried to find if there is an effect of brain fitness exercises on increasing the performance of working memory and attention. They found that these exercises help especially people with more powerful minds, not those with poorer cognitive abilities – which should be the main beneficiaries of this sort of training. Why? Because smart people tend to be more interested in self development, seek out more stimulation and also are more able to motivate themselves long enough (6 weeks of daily exercising) to benefit from the effect of this enduring mental training. 
It seems that societal demands influence the development and interaction of multiple cognitive abilities and knowledge, and giving rise to general intelligence factor. This is something similar to the Flynn effect. The Flynn effect is the substantial and long-sustained increase in fluid and crystallized intelligence test scores (average test scores) measured in many parts of the world from roughly 1930 to the present day. Some explanations have included improved nutrition, better education, and greater environmental complexity. The fact is that this effect tends to be strongly associated with the economic boom of a country.



As I mentioned above, brain fitness exercises increase performance of working memory and attention. In addition, another type of mental exercise – mindfulness meditation is proved to strengthen connections between regions of the brain called Default network and to increase the volume of the hippocampus (a brain structure critical for learning).  The brain’s Default network comprises several brain regions which are viewed as the biological basis of Self, storing our life experiences and contributing to introspection and other self-relevant processing, but also to creativity. Also these people which meditate 20 minutes a day for 90 days develop a more wrinkled cortex – the brain outer layer which is used for the most sophisticated mental abilities – and their brain become more efficient. Animal studies using enriched environment also discovered the effect of environment upon the brain. Enriched environment means housing mice in complex cages, where they have the possibility to play with toys, to explore, to make physical exercises and to interact with other mice. All these impact the brain’s circuits responsible with learning, increased brain plasticity and modify the expression of more than 40 genes involved in learning, building synapses and regulating blood supply in the brain.
So we have an important clue here! The environment, a new, complex environment seems to modify brain’s circuitry involved in learning and also the expression of the genes which build the brain. This process is called epigenetics, and represents the ability of the genes to be changed in their expression by the environment. And also to pass these changes to the next generation. So the environment leaves a mark on the brain, even a genetic mark, and this mark is heritable. This is the explanation for the discovery of the Dutch scientists presented at the beginning of this post. In psychology there is the assumption that genotype (meaning genes) and environment are independent and do not covary. These data suggest they very much do.

The tools we use during our lifetime, the games we play, the gadgets, the internet, all of these seems to shape our genes. Genes are not something created to build “the brain”. They are building specific brains according to the environment were that species use to live.  In the last 5000 years approx. 7 % of our genes have changed. And given that life on Earth is 3,5 billion years old, and our species is 190.000 years old, 5000 years is a blink of an eye! The human brain has adapted to the cultural information from the environment and these adaptations changed the expression of its genes. And some of these changes are passed to the next generation in order to be more adapted. Part of our culture is already in our genes and probably we can say that basically they are a biological form of culture.


Friday, October 11, 2013

Status is a drug

Brain uses the same mechanisms to get attached by somebody and to get addicted to drugs. Given these strange connections, it seems that social support and social status have a strong effect upon the brain, putting us in the position of becoming “addicted to power” and “addicted to public image”. And similar to the sensation of “being high” triggered by drugs, power gives us the sentiment of being above other humans and untouchable.

In these days many people have learnt about the role of body chemicals in romantic love and bonding in general. Despite the initially shocking discovery that human brain uses almost the same circuits for falling in love and for getting addicted to drugs, this scientific knowledge entered gradually into common sense. In all the women magazines you can find now articles about the “love hormones” oxytocin and vasopressin.  But this is not the full story, not even by far. These two ancient hormones are not the solely chemical involved in attachment, and when we start to get the bigger picture some intriguing facts comes to surface.
For instance, oxytocin works together with another brain’s chemical, the famous neurotransmitter – dopamine.  Oxytocin modulates dopamine release in the brain. Dopamine has several receptors to bind in order to exert its effect. One of them is the D2 receptor. And studies have found that these receptors seem to facilitate mother-child bonding. Dopamine interacts with oxytocin especially in the same brain areas involved in drug addiction, which are full of oxytocin receptors. And, strangely, this interaction materializes in social memory and social recognition. D2 is one of the dopamine receptors, and D1 is another one. Laboratory studies  made at University of Texas have shown that dopamine D2 receptor facilitates the establishment of a pair bond, while the D1 receptor inhibits it. So are not the parents to blame? In addition, after sexual intercourse, the dopamine D1 receptor prevents the male to “move on” from the original pair bond to a new bond with another female. Subsequent to mating-induced pair bonding, D1 receptor density increases at the membrane surface of neurons and this increase maintains monogamy by transforming responses toward other females from affiliative interest into aggressiveness. We should put the picture of this receptor on the wall of the City Hall weddings room. These studies were made on rats but there are human studies too, and one of them, made at Northwestern University in Evanston Illinois, have shown that boys with a mutation of the gene responsible with dopamine D2 receptor (mutation which reduces up to 40% of D2 receptor density in the brain areas involved in drugs addiction) tend to begin their sex life earlier and are less inclined toward developing long-lasting relationships with a partner. These individuals may not want to have children or get married, hence confirming the data from animal studies. I think somebody should invent a phone application able to detect this mutation, what do you think girls?



But is more than this. It is not only attachment connected with brain’s mechanisms of addiction. Is leadership, too. A study made in 2010 at Columbia University found a positive correlation between the ability of dopamine to bind with its receptors D2 and perceived social support in humans. Again the brain region targeted was the same intensively studied in drugs addiction. Their data suggest that D2 receptor binding is associated with an individual’s social capital, which may be regarded as a balance between social status and stress reduction by means of social support. High social rank, a strong feeling of social support and low levels of social avoidance are associated with increased dopamine binding with its D2 receptor. Social rank, strong support from the people around you, and a natural tendency to approach people, and to feel comfortable in social situations….Hmm, looks like leadership to me. And which is the connection with drugs? Studies in monkeys have revealed that when a dominant figure is isolated from the group, there is a drop in D2 receptor density in this brain area, and that individual becomes predisposed toward cocaine addiction. Conversely, when an animal becomes the group leader, D2 receptor density increases, thus reflecting the role of these receptors in social reward perception. Also, monkeys that have been exposed to social stress during adolescence are more likely to take drugs and they have lower dopamine binding at D2 receptor in this part of the brain involved in addiction. So, social status is like a drug? You can become addicted to it? Others revealed the implication of other areas in social status, such as the upper region of the frontal lobe. Therefore, electrical recordings from the neurons in this area, showed a stronger activation of the excitatory synapses in rats with high positions in a group hierarchy, compared to the subordinate ones. So your brain functions better when you are the boss. At least you are more excitable.
To summarize, what do we have here? It seems to be a tight connection in the brain between attachment, social status and brain’s mechanisms involved in addiction, but also in performance. If the first are accomplished, it seems the brain enters in a “high mode”, being more excitable, more eager to explore and conquest. And here are the downsides. Studies have found that people driving expensive cars were more likely than other motorists to cut off drivers and pedestrians at a four-way-stop intersection in the San Francisco Bay Area, UC Berkeley researchers observed. Those findings led to a series of experiments that revealed that people of higher socioeconomic status were also more likely to cheat to win a prize and to have an unethical behavior in a company. Genes regulating social behavior are strongly preserved from insects to people. And the brain’s mechanisms they build seem to have a lot in common, despite the differences in size and form. But it seems that evolution takes us by surprise. What makes you fitter and healthier in animal kingdom is not necessary suitable for traffic rules or management. We have to learn how to control these mechanisms in order not to become a stoned baboon driving a Ferrari.

Friday, October 4, 2013

How to open the brain’s windows

The brain is built to learn in a massive way only during the childhood and adolescence. Specific plasticity windows - named critical and sensitive windows - are open within this time interval, which help us to rapidly adapt to the external world. But the fact is that most of our life we live outside these windows and we can see this misfortune almost every day, as adults. Nevertheless, recent studies revealed the secret recipes for re-opening these plasticity windows in adult brain, with tremendous effects on learning, repairing and postponing the old age.

A "critical period" is a time window when external stimuli are mandatory for the normal development of a certain brain circuit. An example could be the learning of language. By contrast, a sensitive period is a time window when environmental experiences have the greatest impact upon a brain circuit. An example is learning a foreign language. A critical period once closed the openness the effect is a reduced effect of sensorial experiences upon the brain. These windows explain the easy of learning which characterizes children and adolescents by contrast to the relative decrease in learning performance specific to adult people. The onset and the duration of a critical period depend on age but also on experience. If a proper exposure or activity is not provided, a brain circuit remains in a waiting state until that input is available.  Not all the brain regions have the same developmental pathway. It matures starting from back to front and from basic functions like vision and movements to more complex abilities like language, problem solving or understanding others. In the visual cortex, the critical period closed around the age of 5 in humans, after this milestone the brain’s capacity to be changed by experience being significantly reduced. It is interesting that any foreign language learned before the age of 11 is superimposed in the brain on the same area of the native language, within the Broca area of language. By contrast, any foreign language learned after this age is saved in a different area within the Broca area. Also, learning a foreign language after this age requires much more effort and good results takes more time.  If a child is not exposed to native language until age of 11, afterwards he/she can learn only the words but not the grammar, hence being impossible to speak normally. Critical periods dictate also over some learning processes like extinction of a traumatic memory or a phobia. It is known that after a successful therapeutic session, these memories are not erased, are only inhibited (this is why they can pop-up sometimes and the stressful memory reappears). At least this is happening in the adult brain. But in the child brain, during  his/her first years of life, the extinction involves the permanent erasure of that memories. In the adult brain a proteins network is developed around the neurons and this network secures the memories for a life time. So is not possible to be erased anymore. It is striking that the proteins that build this network are the same that build the cartilages from the trachea, bronchi and heart.

The protein network which protect our memories from erasure (with red)(from Gogolla et al., 2009. Science, 325:1258-1261)

Given the fact that most of our life we spend as adults and the environment around us is changing all the time, is critical for an adult to preserve the learning abilities he/she use to have as an adolescent. Accidents that happened  to an adult brain are harder to be repaired and sometimes the repair process is not totally  successful. And the closure of the critical and sensitive periods are to be blamed for this. But it is possible to re-open these windows in an adult brain?  Experiments revealed that several factors are involved in triggering a critical or a sensitive period.  For instance, the therapy with antidepressant medication, such Prozac, seems to facilitate the plasticity of adult brain and it is prescribed, along with the physiotherapy, for the stroke victims. Also, enriched environment it is documented to have the same beneficial effects with the antidepressant medication, at least for the animals suffering of amblyopia.  Enriched environment provides a combination of multisensory stimulation, physical activity, social interactions and facilitation of exploratory behavior.   Enriched environment impacts the brain leading to an enhancement of cognitive  functions (especially learning and memory) but also positively impacts emotional reactivity and stress response.   Also it facilitates the growth of the grey matter hence influencing the weight of the brain, the number of synapses and the birth of new neurons. It also stimulates the expression of 41 genes known to be involved in learning and memory, plasticity, cellular growth, the genesis of blood vessels, and neuronal excitability. Even more ,  enriched environment seems to stimulates the anti-oxidative mechanisms of the organism, decreasing the inflammation and boosting immunity. It is interesting that enriched environment facilitates the maturation of visual system even in the case of total absence of visual experiences! Studies made on rats have shown that housing the pregnant female in this type of environment during the last semester of pregnancy leads to a more rapid development of pups’ visual system.    Furthermore, running in a wheel leads to a 2-fold increase in the number of neurons in their pups’ brain and also a better working memory for them, once they give birth.
A critical period can be induced in adult humans through non-invasive techniques such as enriched environment (as I already mentioned) but also by incremental training and educational video games, all of these putting the brain into a “learning mode”. Studies have shown that people which use to train themselves with action videogames, present an enhancement in visual acuity, effect not possible to be obtained by playing non-action video games. This emphasizes the role of some specific features of action games in maintaining attention and stimulating some neurotransmitters like dopamine and noradrenaline which are critical for brain plasticity. Studies made on animals found that the modification of the training protocols in order to contain incremental changes of the sensorial experiences leads to enhancement of the learning ability. The same results have been seen on human subjects exposed 2-3 weeks on various learning experiences previous to the exposure to the target material to be learned. This is called metaplasticity, or the intentionally process of inducing plasticity in the brain.

  All of this data show that our brain is a life time project; it can help us only if we help it. It’s a sort of symbiosis. In addition, the brain is the only organ in our body we can keep young, at least for a while. The “know-how” of this process is not written in our genes, it depends by the knowledge we gathered with the technology it helps us to develop. So we can say neuroscience is the brain’s effort to discover how it is built, how to repair itself and how to enjoy the world as much as is possible.