So we finally reach the end of the book, Brain Rules. Here's where we've been:
Rule 1: Exercise
Rule 2: Survival
Rule 3: Wiring
Rule 4: Attention
Rule 5: Short-Term Memory
Rule 6: Long-Term Memory
Rule 7: Sleep
Rule 8: Stress
Rule 9: Sensory Integration
Rule 10: Vision
Rule 11: Gender
Rule 12: Exploration
Rule #12: "We are powerful and natural explorers."
Medina ends the book with these words: "The greatest Brain Rule of all is something I cannot prove or characterize, but I believe it with all my heart... it is the importance of curiosity" (279). Medina's mother fed every passing interest he had growing up, from dinosaurs to space to mythology, even atheism. At the other end of life, his 100 year old grandfather demonstrated a fascination with new knowledge. The point is that Medina believes we are built to be life-long learners and we are only taught to go to sleep intellectually by society.
Until just after the year 2000, it was commonly thought that the brain did not generate any new cells after birth. But it is now recognized that the learning sections of the brain continue to generate new cells throughout life and that these cells are as malleable as a babies brain cells. Medina believes that our brains developed the ability to learn and improvise from "chaotic, reactive, information-gathering experiences" early on as a species (271). "One of our best attributes is the ability to learn through a series of increasingly self-corrected ideas."
A good deal of this chapter addresses child development and indeed Medina's own engagement with his own children. Forty years ago, it was generally believed that we start out more or less as a "blank slate" on which our experiences write. Today, we realize that a lot of the human brain comes pre-wired with various drives and processes.
A baby less than an hour old can stick out its tongue in imitation of someone else sticking out his or hers. We have "pre-loaded information gathering strategies" (267). For example, we have a kind of cell called "mirror neurons" that imitate in our minds the things we see. Our right, pre-frontal cortex predicts and evaluates when we are wrong about something. Then something called the "anterior cingulate cortex" signals that we need to change our behavior.
We are wired to test hypotheses. We get bit by a snake or a bee, we don't get near it next time. We make observations with our senses. We form hypotheses about what is going on. We experiment. We draw conclusions.
Our brains develop in predictable ways. At 18 months, we learn that objects continue to exist even after we do not see them, such as when you hide a cup under a cloth. The "terrible twos" are when we can really distinguish our own wills from those of others. We begin to experiment with doing the opposite of what our parents want us to do to see what happens.
Medina ends the chapter and the book with ideas about how educational institutions might be structured to capture the exploratory dimension of the human mind. He thinks medical schools might very well be an excellent model. They have 1) consistent exposure to the real world. For example, you often learn on site at a hospital.
Secondly, they give constant exposure to people in the real world, using faculty who work in the field as well as teach. Finally, they give exposure to individuals engaged in practical research, research laboratories. He gives another example of how you might set up a college of education that studies the brain, but he thinks this model might be used with other areas of education too, such as a business school.
Showing posts with label brain research. Show all posts
Showing posts with label brain research. Show all posts
Thursday, January 31, 2013
Wednesday, January 30, 2013
Brain Rule #11: Gender
My summaries of the book Brain Rules continue...
________________
Chapter 11: Gender
Rule #11: Male and female brains are different.
Stephen Jay Gould said the following about the nature-nature controversy, the question of whether our inherited genetics or the environment we grow up in affects who we are more: "It is logically, mathematically, and scientifically impossible to pull them apart" (252). Society has expectations of men and women that affect our perceptions and expectations. Our "sex" may be biological, but "gender" is mostly a matter of social expectations.
In one experiment, a corporate executive was said to be a male to one group, a female to another. With no other difference in the description, the group described the male as likable and competent, the female as likable and not very competent. Two other groups were given the same descriptions with the added information that the executive was a superstar on the rise. They again described the male as likable and very competent, the female as very competent but unlikable, perhaps even hostile.
The genetic differences between male and female come from our different chromosome make-up. Women have two X chromosomes. Men have an X and a Y chromosome. We know now, of course, that the man determines the sex of a child. The woman contributes an X chromosome to the child. Then the man either contributes another X chromosome to make a girl or a Y chromosome that makes a boy.
The X chromosome is much longer (some 1500 genes) than a Y one (less than 100)--and the far more significant of the two. The default setting of a mammalian embryo is to make a female. A small gene in the middle of a Y chromosome called SRY will make the embryo become male.
Because a female has two Xs from which to chose, she genetically shuts off half the genetic material somewhat randomly, some from the father and some from the mother. But the male has to use all the X material from his mother. This implies that a male is more genetically biased toward his mother. It also implies that a male has more at stake if a gene on the X chromosome is damaged.
There are also some regular differences in the brains of men and women. Men tend to have a much larger amygdala than women, the part of the brain that creates and remembers emotions. The amygdala of a woman also tends to interact more with the left side of the brain, male amygdalas with the right. This is not the right brain-left brain folk tale (both sides of the brain are used in both creativity and analysis). But the right side of the brain tends more to get the gist of things, the left side more the details. It thus does seem to be true that women tend to remember more the details of an emotional event while men more remember the gist.
Male brains generate serotonin about 52% faster than women do. Serotonin is sometimes connected to the regulation of mood and maintenance of a sense of well being, but brain scientists strongly disagree over such things. The precise significance of brain differences relating to the size of the amygdala and the rate of serotonin production are not agreed.
Studies of differences between male and female brains have to do with populations rather than individuals. That is to say, these analyses have to do with large groups of men and women rather than any individual male or female in particular. Just because most male or female brains would seem to function in a particular way does not mean that all do.
There are, however, some observable trends. Men are more likely to have mental retardation than women. Men tend to have more severe cases of schizophrenia than women. But women are twice as likely to experience chronic depression than men. Men are more likely to be anti-social or be addicted to alcohol or drugs. Women are more likely to have anxiety.
Women tend to be better at verbal communication than men, and they use both sides of their brains when speaking and processing verbal information. Men primarily use one of the hemispheres. Women tend to cement relationships through conversation, while boys seem to do it by "commotion," by physical interaction and competition.
When boys jockey for status, the dominant one tends to give orders, the less dominant tend to withdraw. In some studies, women tend not to give top down orders. If the male leader says, "Do this," the female more likely to say, "Let's do this." Intimacy among females often involves sharing secrets.
Medina's ideas have to do with paying attention to gender differences. He suggests in the workplace that an employers might experiment a little with teams of varied gender arrangements to see how it affects projects. He suggests that women are not more emotional than men but that they have more details of emotional experiences to deal with than men do. In the classroom, he suggests that boys or girls may need some separate attention to keep social dynamics from preventing them from reaching their potential.
Brain Rule #10: Vision
My summaries of the book Brain Rules continue...
________________
Chapter 10: Vision
Rule #10: Vision trumps all other senses.
"We see with our brains" (224). In the previous chapter, Medina has talked about the model that sees our senses sending information to brain centers and then on to higher regions of perception. He suggests that the process is much messier, involving interaction with other senses early in the process and a "top down" element of interpretation that results in differing interpretations of the same experiences.
Our vision is a great illustration of this messiness. For one thing, processing of vision seems to start not at our vision center at the back of the brain but with the retina itself at the back of our eyes. Our retina takes light patterns and makes partial "movies" called "tracks" (225). One of these tracks involves outlines and edges, another processes motion, another has to do with shadows.
Perhaps as many as a dozen little amateur "filmmakers" send these movies simultaneously to the back of the brain for integration and further interpretation. If one of these tracks is defective, a person may not be able to discern motion or some other central element of vision. The tracks go to the thalamus and then emerge in greater combination.
Eventually the information flows in two streams. The ventral stream recognizes what an object is along with its color. The dorsal stream recognizes location and whether something is moving. The "association regions" mentioned in the previous chapter work to integrate these electrical signals.
Far from the brain seeing exactly what is there, it makes some guesses and fills in some blanks. It fills in the blind spot in our sight, for example. The brain takes the differing images coming from each eye and combines them together so that you only see one outside picture. People with Charles Bonnet Syndrome actually hallucinate people and things that they know are not there. Their brain simply fills in the details wrongly. The brain devotes about half of its resources to the act of seeing.
A lot of what we see is actually our brain guessing what is out there based on prior experience. Many will be acquainted with "phantom-limb" experiences. This is where the brain continues to feel a limb that is actually no longer there. Some individuals experience pain in this limb that no longer exists. One way to alleviate that pain is to put a mirror up against a remaining limb so that it looks like there is another limb beside it. Sometimes, the vision convinces the subconscious enough that the pain will diminish.
An average person might remember 10% of a lecture. If pictures are combined appropriately with the lecture, that figure goes up to 65%. The dominance of vision over all the other senses begins in infancy. It is reflected in our very DNA, where scientists would say vision has taken over massive amounts of genetic material devoted to smell previously, about 60%.
Medina ends the chapter with some ideas. For example, he suggests that we throw out our old PowerPoint presentations, the ones with way too much text on them and no pictures. "Less text, more pictures" (238) brought USA Today criticism in 1982 when it started, but it is the most read newspaper in the United States today. Pictures grab attention because the brain is wired to pay attention to color, orientation, size, and motion. It helped us survive in the Serengeti in an earlier phase of the species.
Software allows people today to create simple but effective computer animations. Medina tells how his career choice was inspired by an early animated short in 1959 called Donald in Mathmagic Land. "We learn and remember best through pictures, not through written or spoken words" (240).
________________
Chapter 10: Vision
Rule #10: Vision trumps all other senses.
"We see with our brains" (224). In the previous chapter, Medina has talked about the model that sees our senses sending information to brain centers and then on to higher regions of perception. He suggests that the process is much messier, involving interaction with other senses early in the process and a "top down" element of interpretation that results in differing interpretations of the same experiences.
Our vision is a great illustration of this messiness. For one thing, processing of vision seems to start not at our vision center at the back of the brain but with the retina itself at the back of our eyes. Our retina takes light patterns and makes partial "movies" called "tracks" (225). One of these tracks involves outlines and edges, another processes motion, another has to do with shadows.
Perhaps as many as a dozen little amateur "filmmakers" send these movies simultaneously to the back of the brain for integration and further interpretation. If one of these tracks is defective, a person may not be able to discern motion or some other central element of vision. The tracks go to the thalamus and then emerge in greater combination.
Eventually the information flows in two streams. The ventral stream recognizes what an object is along with its color. The dorsal stream recognizes location and whether something is moving. The "association regions" mentioned in the previous chapter work to integrate these electrical signals.
Far from the brain seeing exactly what is there, it makes some guesses and fills in some blanks. It fills in the blind spot in our sight, for example. The brain takes the differing images coming from each eye and combines them together so that you only see one outside picture. People with Charles Bonnet Syndrome actually hallucinate people and things that they know are not there. Their brain simply fills in the details wrongly. The brain devotes about half of its resources to the act of seeing.
A lot of what we see is actually our brain guessing what is out there based on prior experience. Many will be acquainted with "phantom-limb" experiences. This is where the brain continues to feel a limb that is actually no longer there. Some individuals experience pain in this limb that no longer exists. One way to alleviate that pain is to put a mirror up against a remaining limb so that it looks like there is another limb beside it. Sometimes, the vision convinces the subconscious enough that the pain will diminish.
An average person might remember 10% of a lecture. If pictures are combined appropriately with the lecture, that figure goes up to 65%. The dominance of vision over all the other senses begins in infancy. It is reflected in our very DNA, where scientists would say vision has taken over massive amounts of genetic material devoted to smell previously, about 60%.
Medina ends the chapter with some ideas. For example, he suggests that we throw out our old PowerPoint presentations, the ones with way too much text on them and no pictures. "Less text, more pictures" (238) brought USA Today criticism in 1982 when it started, but it is the most read newspaper in the United States today. Pictures grab attention because the brain is wired to pay attention to color, orientation, size, and motion. It helped us survive in the Serengeti in an earlier phase of the species.
Software allows people today to create simple but effective computer animations. Medina tells how his career choice was inspired by an early animated short in 1959 called Donald in Mathmagic Land. "We learn and remember best through pictures, not through written or spoken words" (240).
Brain Rule #9: Sensory Integration
My summaries of the book Brain Rules continue...
________________
Chapter 9: Sensory Integration
Rule #9: Stimulate more of the senses.
One model for how we process information from our senses goes something like the following. It starts with sensation--our five senses are stimulated by our environment (sensation). Then you might think that the thalamus, an egg shaped structure in the middle of the brain, routs those sensations to the respective sense corners of the brain (routing)--sight, sound, etc. Finally, their conclusions are merged and sent to the higher parts of the brain for perception of what they mean.
Although the evidence is not definitive, Medina thinks it is leaning toward a messier process. In this model, the senses begin to confer with each other almost immediately. The overall process is much the same except that perception is going on from the very beginning as the senses interact with each other.
Perception involves both "bottoms up" and "top down" activities. Association cortices in the brain connect the sense data that has come up from our senses and been processed by the key sensory areas of the brain (bottoms up) with past experiences and memories that it relates to them (top down). The result is that two people experiencing the same sensory stimulation can have different perceptions based on their past experiences. Accordingly, we have no guarantee that we experience the world as it actually is.
Our varied senses confer with each other in the process of perception, all along the way. If you see a video where someone says "ga" and the sound "ba" is dubbed over it, many will hear something like "da," a compromise between your sight and hearing (McGurk effect). On the positive side, the use of multiple senses in learning improves the likelihood of retention.
"When touch is combined with visual information, recognition learning leaps forward by almost 30 percent, compared with touch alone" (208). Multisensory learning can improve learning 50 to 75 percent. Richard Mayer puts down several rules for multimedia presentations:
Unlike the other senses, electrical impulses from smell bypasses the thalamus in routing and go directly to destinations in the brain like the amygdala, which controls emotions. Smell can thus have a powerful and immediate effect on us. The Proust effect is when smell evokes strong memories. Smell stimuli also go directly to the decision making center of our brain.
As far as ideas, Medina suggests that the first part of a lecture involve multisensory stimulation. The combination of smell with a sales environment can significantly improve sales of particular items. Medina suggests that pairing particular smells with particular learning content would improve memory if that smell were reintroduced during testing.
________________
Chapter 9: Sensory Integration
Rule #9: Stimulate more of the senses.
One model for how we process information from our senses goes something like the following. It starts with sensation--our five senses are stimulated by our environment (sensation). Then you might think that the thalamus, an egg shaped structure in the middle of the brain, routs those sensations to the respective sense corners of the brain (routing)--sight, sound, etc. Finally, their conclusions are merged and sent to the higher parts of the brain for perception of what they mean.
Although the evidence is not definitive, Medina thinks it is leaning toward a messier process. In this model, the senses begin to confer with each other almost immediately. The overall process is much the same except that perception is going on from the very beginning as the senses interact with each other.
Perception involves both "bottoms up" and "top down" activities. Association cortices in the brain connect the sense data that has come up from our senses and been processed by the key sensory areas of the brain (bottoms up) with past experiences and memories that it relates to them (top down). The result is that two people experiencing the same sensory stimulation can have different perceptions based on their past experiences. Accordingly, we have no guarantee that we experience the world as it actually is.
Our varied senses confer with each other in the process of perception, all along the way. If you see a video where someone says "ga" and the sound "ba" is dubbed over it, many will hear something like "da," a compromise between your sight and hearing (McGurk effect). On the positive side, the use of multiple senses in learning improves the likelihood of retention.
"When touch is combined with visual information, recognition learning leaps forward by almost 30 percent, compared with touch alone" (208). Multisensory learning can improve learning 50 to 75 percent. Richard Mayer puts down several rules for multimedia presentations:
- We learn by words and pictures better than from words alone.
- Learning is better when words and pictures appear at the same time rather than one after the other and close to each other rather than far apart.
- Learning is better when extra information is included.
- Students learn better from animation and narration than from animation and on-screen text.
Unlike the other senses, electrical impulses from smell bypasses the thalamus in routing and go directly to destinations in the brain like the amygdala, which controls emotions. Smell can thus have a powerful and immediate effect on us. The Proust effect is when smell evokes strong memories. Smell stimuli also go directly to the decision making center of our brain.
As far as ideas, Medina suggests that the first part of a lecture involve multisensory stimulation. The combination of smell with a sales environment can significantly improve sales of particular items. Medina suggests that pairing particular smells with particular learning content would improve memory if that smell were reintroduced during testing.
Saturday, January 26, 2013
Brain Rule #8: Stress
My summaries of the book Brain Rules continue...
________________
Chapter 8: Stress
Rule #8: Stressed brains don't learn the same way.
What is stress? Medina mentions research that identifies stress with three simultaneous factors. First, a person will experience an aroused physiological response measurable by an outside party. Second, the thing causing the stress must be perceived as aversive. Finally, the person experiencing it will not feel in control of the stressor.
The body's response to stress was meant to address situations that lasted for seconds--like getting away from a saber-toothed tiger. The body releases adrenaline. It also releases a hormone called cortisol that kicks in with extra power. The problem is chronic stress, when the system does not return to normal. Our arteries get damaged, develop scars, and clog. Our white blood cells and immune system are weakened and we get sick more easily.
In an instant, stress greatly improves our memory. But prolonged stress cuts our memory and ability to make decisions by as much as 50%. Cortisol disconnects neural networks and kill cells in our hippocampus, the part of our brain that works to form long term memories.
A protein called BDNF counteracts the force of the cortisol, but chronic stress can completely shut it off to where you won't even remember a traumatic event. It can bring a debilitating depression that does not even try to escape a situation when it could. Some people can handle stress better than others. But at some point, stress becomes toxic, what the researcher Bruce McEwen calls the "allostatic load," the tipping point when your body begins to lose to stress.
The rule of this chapter is that "stressed brains do not learn the same as non-stressed brains" (184). They don't do much learning at all. "One of the greatest predictors of performance in school turns out to be the emotional stability of the home" (183). "Children living in high-anxiety households would not perform as well academically as kids living in more nurturing households" (184). For example, it is not divorce per se but overt conflict in a home that predicts grade failure.
Stress is an enemy of the work place too. Depression kills problem-solving abilities. It drastically increases health care costs. It often leads to firing, requiring the need for training new workers. The type of stress in the workplace, the employees home life, and the balance between stimulation and boredom determine whether a workplace is stressful. One of the worst formulas for workplace stress is when much is expected of a person but he or she does not have control over the outcome.
Medina ends the chapter as usual with some ideas. The stability of a home is so crucial to the learning of a child that parental training to reduce stress on children would be ideal. Medina would make education a "family affair" from a week after birth. Since the typical time of having children and some of the most productive work years for a person coincide, Medina's perfect world would see child care at places of work and marital training to help new parents cope with the new found stress of a new child.
________________
Chapter 8: Stress
Rule #8: Stressed brains don't learn the same way.
What is stress? Medina mentions research that identifies stress with three simultaneous factors. First, a person will experience an aroused physiological response measurable by an outside party. Second, the thing causing the stress must be perceived as aversive. Finally, the person experiencing it will not feel in control of the stressor.
The body's response to stress was meant to address situations that lasted for seconds--like getting away from a saber-toothed tiger. The body releases adrenaline. It also releases a hormone called cortisol that kicks in with extra power. The problem is chronic stress, when the system does not return to normal. Our arteries get damaged, develop scars, and clog. Our white blood cells and immune system are weakened and we get sick more easily.
In an instant, stress greatly improves our memory. But prolonged stress cuts our memory and ability to make decisions by as much as 50%. Cortisol disconnects neural networks and kill cells in our hippocampus, the part of our brain that works to form long term memories.
A protein called BDNF counteracts the force of the cortisol, but chronic stress can completely shut it off to where you won't even remember a traumatic event. It can bring a debilitating depression that does not even try to escape a situation when it could. Some people can handle stress better than others. But at some point, stress becomes toxic, what the researcher Bruce McEwen calls the "allostatic load," the tipping point when your body begins to lose to stress.
The rule of this chapter is that "stressed brains do not learn the same as non-stressed brains" (184). They don't do much learning at all. "One of the greatest predictors of performance in school turns out to be the emotional stability of the home" (183). "Children living in high-anxiety households would not perform as well academically as kids living in more nurturing households" (184). For example, it is not divorce per se but overt conflict in a home that predicts grade failure.
Stress is an enemy of the work place too. Depression kills problem-solving abilities. It drastically increases health care costs. It often leads to firing, requiring the need for training new workers. The type of stress in the workplace, the employees home life, and the balance between stimulation and boredom determine whether a workplace is stressful. One of the worst formulas for workplace stress is when much is expected of a person but he or she does not have control over the outcome.
Medina ends the chapter as usual with some ideas. The stability of a home is so crucial to the learning of a child that parental training to reduce stress on children would be ideal. Medina would make education a "family affair" from a week after birth. Since the typical time of having children and some of the most productive work years for a person coincide, Medina's perfect world would see child care at places of work and marital training to help new parents cope with the new found stress of a new child.
Wednesday, January 23, 2013
Brain Rule #7: Sleep
My summaries of the book Brain Rules continue...
________________
Chapter 7: Sleep
Rule #7: Sleep well, think well.
We spend about a third of our time on the planet sleeping. Those few people who have "Fatal Familial Insomnia" and cannot sleep eventually die.
Randy Gardner, the father of sleep research, came to the conclusion early on that we have two opposing drives inside us with regard to sleep. Both of them are active all the time, whether we are awake or asleep. The one is the "circadian arousal system" (process C). It tries to keep us awake. The other is the "homeostatic sleep drive" (process S). It wants to put us to sleep.
Neither of these "armies" ever win the war. They lead us through a rhythm of being sleep and awake, and this rhythm takes place whether we are in a cave or outdoors. After 16 hours of active consciousness, process C will generally lose to process S. Eight hours later, process S usually loses and we wake up.
We do vary a little in our sleep needs and preferences. About 1 in 10 are "larks" whose bodies prefer to get up at least by 6am, the early birds. They're most alert about noon. About 2 in 10 are "owls" whose bodies want to stay up to all hours of the night. They're most alert about 6pm. The rest of us, about 7 in 10, are "hummingbirds" who are somewhere in the middle.
Sleep research has shown that those cultures that institute naps have recognized something research has substantiated. Humans do well to have an afternoon nap. Audiences lose attention. There are more traffic accidents than at any other time of the day. A 30 minute nap in this zone of the day significantly improves productivity.
Sleep helps learning and lack of sleep hurts it. Allowing someone to sleep on something improves insight, as much as tripling the benefit of learning. In short, "Sleep is rather intimately involved in learning" (163). Apparently, the brain consolidates its learning during sleep.
Medina ends the chapter with some possible suggestions. First, work schedules would optimally match "chronotypes" (larks-owls). "Twenty percent of the workforce is already at sub-optimal productivity in the current 9-to-5 model" (165). During teenage years, more individuals are owls than even in adulthood, suggesting that high school shouldn't start too early in the morning.
Creating space for employees to have an half-hour nap in the afternoon would probably increase their performance 34 percent. Finally, sleeping on things will generally improve our learning.
________________
Chapter 7: Sleep
Rule #7: Sleep well, think well.
We spend about a third of our time on the planet sleeping. Those few people who have "Fatal Familial Insomnia" and cannot sleep eventually die.
Randy Gardner, the father of sleep research, came to the conclusion early on that we have two opposing drives inside us with regard to sleep. Both of them are active all the time, whether we are awake or asleep. The one is the "circadian arousal system" (process C). It tries to keep us awake. The other is the "homeostatic sleep drive" (process S). It wants to put us to sleep.
Neither of these "armies" ever win the war. They lead us through a rhythm of being sleep and awake, and this rhythm takes place whether we are in a cave or outdoors. After 16 hours of active consciousness, process C will generally lose to process S. Eight hours later, process S usually loses and we wake up.
We do vary a little in our sleep needs and preferences. About 1 in 10 are "larks" whose bodies prefer to get up at least by 6am, the early birds. They're most alert about noon. About 2 in 10 are "owls" whose bodies want to stay up to all hours of the night. They're most alert about 6pm. The rest of us, about 7 in 10, are "hummingbirds" who are somewhere in the middle.
Sleep research has shown that those cultures that institute naps have recognized something research has substantiated. Humans do well to have an afternoon nap. Audiences lose attention. There are more traffic accidents than at any other time of the day. A 30 minute nap in this zone of the day significantly improves productivity.
Sleep helps learning and lack of sleep hurts it. Allowing someone to sleep on something improves insight, as much as tripling the benefit of learning. In short, "Sleep is rather intimately involved in learning" (163). Apparently, the brain consolidates its learning during sleep.
Medina ends the chapter with some possible suggestions. First, work schedules would optimally match "chronotypes" (larks-owls). "Twenty percent of the workforce is already at sub-optimal productivity in the current 9-to-5 model" (165). During teenage years, more individuals are owls than even in adulthood, suggesting that high school shouldn't start too early in the morning.
Creating space for employees to have an half-hour nap in the afternoon would probably increase their performance 34 percent. Finally, sleeping on things will generally improve our learning.
Wednesday, December 19, 2012
Brain Rule #6: Long Term Memory
My summaries of the book Brain Rules continue...
________________
Chapter 6: Long Term Memory
In summarizing this chapter, it is perhaps easiest to begin where it ends. It ends by returning to H.M., who was mentioned in chapter 5. In the early 1950s, H.M. had his hippocampus removed in the center of his brain. As a result, he cannot convert short term memory into long term memory. He has no memories since the 1940s and doesn't recognize his own face in the mirror.
What is interesting is that he does not remember anything since about eleven years before his surgery. The implication is that it can take over a decade for short term memories to solidify fully. Even though long term memory is apparently stored in various parts of the cerebral cortex, the outer part of our brain, the hippocampus continues to be involved in its solidification for as much as a decade after an event occurs. The process seems to work something like the following.
First, long term memory comes as a result of ongoing interactions between the hippocampus and the cerebral cortex, "multiple reinstatements" of the same memory (141). It starts with "working memory," which has auditory, visual, and executive components. The executive component keeps track of how the various components of working memory fit together.
Secondly, "These reinstatements are directed by the hippocampus perhaps for years" (141). Like the components of working memory, there appear to be different systems of long term memory as well, although the categories are less agreed on. However, there may be "semantic" memory systems for details (126). There may be "episodic" memory that have to do with past events. An important subset of episodic memory may be "autobiographical" memory about your own past.
The key to conversion from short term to long term memory seems to be repetition. "Repetition, doled out in specifically timed intervals, is fixative" (130). When it comes to experiences, talking about an event immediately after it occurs significantly enhances the long term memory of the event (131). Otherwise, a great deal of memory loss occurs in the first hour or two after initial exposure.
After the initial learning, you should deliberately re-expose yourself to information in fixed, spaced intervals (133). Do so "more elaborately" as you re-expose yourself. "Increasingly limited exposures can result in increasingly stronger responses" (134), like a whiff of someone's perfume or music you associate with someone.
The first spark of memory will fade in about 90 minutes if not re-fired. In the formation of long term memory, its "consolidation," there will have to be continued communication over years between the hippocampus and the cortex. This can happen even while you sleep. Neurologists aren't quite sure where exactly the memories are as the long term consolidation takes place. One person called it "nomadic memory" as it may wander around the brain's "neural wilderness" (140). A memory may actually come to final rest in the same region as it started.
So, thirdly, a memory eventually becomes permanently stored in the cortex (141-42). H.M. could remember things from 11 years before his surgery, memories that did not depend on the hippocampus at all. But, fourthly, retrieving long term memories for the rest of us immediately makes them changeable again (142). "When previously consolidated memories are recalled from long-term storage into consciousness, they revert to their previously labile, unstable natures" (127). Unfortunately, "permanent storage exists in our brains only for those memories we choose not to recall."
For short term memory retrieval, we recall like someone going through the stacks in a library to find a book (reproductive retrieval). But as time goes by, retrieving a memory is more like a Sherlock Holmes investigation (128). We have fragments of memory that we try to piece together and re-enact (fragmentary memory). "Over time, the brain's many retrieval systems seem to undergo a gradual switch from specific and detailed reproductions to this more general and abstracted recall" (129).
Meanwhile, "forgetting allows us to prioritize events" (143). Without the ability to forget, we would not be able to see the big picture. Forgetting allows us to find the common points between things and discover larger, repeating patterns.
What impact does an understanding of long term memory have? Medina suggests an experimental learning regiment that is quite intriguing. He would divide teaching moments into 25 minute modules which would be repeated in 90 minute intervals throughout the day. Then every third or fourth day they would review material from the previous 72-96 hours. Then critical information would be repeated on a yearly or semi-yearly basis. He even thinks it would be helpful to bring practitioners in the field into dialog with the university, creating life long memory refreshment.
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Chapter 6: Long Term Memory
In summarizing this chapter, it is perhaps easiest to begin where it ends. It ends by returning to H.M., who was mentioned in chapter 5. In the early 1950s, H.M. had his hippocampus removed in the center of his brain. As a result, he cannot convert short term memory into long term memory. He has no memories since the 1940s and doesn't recognize his own face in the mirror.
What is interesting is that he does not remember anything since about eleven years before his surgery. The implication is that it can take over a decade for short term memories to solidify fully. Even though long term memory is apparently stored in various parts of the cerebral cortex, the outer part of our brain, the hippocampus continues to be involved in its solidification for as much as a decade after an event occurs. The process seems to work something like the following.
First, long term memory comes as a result of ongoing interactions between the hippocampus and the cerebral cortex, "multiple reinstatements" of the same memory (141). It starts with "working memory," which has auditory, visual, and executive components. The executive component keeps track of how the various components of working memory fit together.
Secondly, "These reinstatements are directed by the hippocampus perhaps for years" (141). Like the components of working memory, there appear to be different systems of long term memory as well, although the categories are less agreed on. However, there may be "semantic" memory systems for details (126). There may be "episodic" memory that have to do with past events. An important subset of episodic memory may be "autobiographical" memory about your own past.
The key to conversion from short term to long term memory seems to be repetition. "Repetition, doled out in specifically timed intervals, is fixative" (130). When it comes to experiences, talking about an event immediately after it occurs significantly enhances the long term memory of the event (131). Otherwise, a great deal of memory loss occurs in the first hour or two after initial exposure.
After the initial learning, you should deliberately re-expose yourself to information in fixed, spaced intervals (133). Do so "more elaborately" as you re-expose yourself. "Increasingly limited exposures can result in increasingly stronger responses" (134), like a whiff of someone's perfume or music you associate with someone.
The first spark of memory will fade in about 90 minutes if not re-fired. In the formation of long term memory, its "consolidation," there will have to be continued communication over years between the hippocampus and the cortex. This can happen even while you sleep. Neurologists aren't quite sure where exactly the memories are as the long term consolidation takes place. One person called it "nomadic memory" as it may wander around the brain's "neural wilderness" (140). A memory may actually come to final rest in the same region as it started.
So, thirdly, a memory eventually becomes permanently stored in the cortex (141-42). H.M. could remember things from 11 years before his surgery, memories that did not depend on the hippocampus at all. But, fourthly, retrieving long term memories for the rest of us immediately makes them changeable again (142). "When previously consolidated memories are recalled from long-term storage into consciousness, they revert to their previously labile, unstable natures" (127). Unfortunately, "permanent storage exists in our brains only for those memories we choose not to recall."
For short term memory retrieval, we recall like someone going through the stacks in a library to find a book (reproductive retrieval). But as time goes by, retrieving a memory is more like a Sherlock Holmes investigation (128). We have fragments of memory that we try to piece together and re-enact (fragmentary memory). "Over time, the brain's many retrieval systems seem to undergo a gradual switch from specific and detailed reproductions to this more general and abstracted recall" (129).
Meanwhile, "forgetting allows us to prioritize events" (143). Without the ability to forget, we would not be able to see the big picture. Forgetting allows us to find the common points between things and discover larger, repeating patterns.
What impact does an understanding of long term memory have? Medina suggests an experimental learning regiment that is quite intriguing. He would divide teaching moments into 25 minute modules which would be repeated in 90 minute intervals throughout the day. Then every third or fourth day they would review material from the previous 72-96 hours. Then critical information would be repeated on a yearly or semi-yearly basis. He even thinks it would be helpful to bring practitioners in the field into dialog with the university, creating life long memory refreshment.
Wednesday, October 03, 2012
Brain Rule 2: The Brain Evolved...
For various reasons I find myself having to read through a book called Brain Rules. The first two chapters are fascinating, although no doubt many will push back on its evolutionary approach. The first chapter gives John Medina's first rule: Exercise! Even a little exercise improves brain power.
He takes an evolutionary perspective. Humans evolved to move. That's how we survived as a species, he will say in the second chapter. We moved 12 miles a day on average in the early days of our ancestors, he says. It's stupid to cut recess out of public school education, he says. It's like eating less in order to gain weight. I think this is the chapter where he says it cuts the risk of Alzheimers by something like 60%.
His second rule is that the brain evolved too. It's a fascinating chapter. "The brain appears to be designed to (1) solve problems (2) related to surviving (3) in an unstable outdoor environment, and (4) to do so in nearly constant motion" (31-32). It did this so that we could survive long enough to have sex, have children, and live long enough to protect them to grow up to have more sex and children. From a Christian perspective, I might add, it's not a particular grandiose view of humanity, but we are at least this much. We may be more, but we are at least this much.
Later on in the chapter, he has a rather crass, even if possibly accurate sense of how the human womb evolved. The key to the survival of our species, Medina claims, is not that we got stronger but that we got smarter (32, 37). This meant that those with bigger brains--and thus bigger heads--survived more effectively than others. This meant that women with larger wombs survived birth better--and that babies came out sooner. Now parenting and childhood had to take place for years, unlike species where the offspring come out pretty much ready to go.
Medina has a fascinating version of human evolution. We should keep in mind not only that his account may be debatable to some Christians but also among evolutionary experts themselves. Medina traces the key to our evolution to fundamental changes in the earth's weather (35). It knocked our human ancestors out of the trees and onto flat ground that made offspring who stood upright and moved around a lot better suited to survive than those bent over.
Here is one of the take-aways from this chapter. We survived as a species, he says in so many words, because we became a species that improvises and adapts to new environments rather than staying in the same place. We moved out all over the globe and adapted wherever we went. His take-away for learning is something called Variability Selection Theory. Learning is the interaction between two powerful features of the brain: "a database in which to store a fund of knowledge, and the ability to improvise off of that database. One allows us to know when we've made mistakes. The other allows us to learn from them" (37-38).
His conclusion is that "any learning environment that deals with only the database instincts or only the improvisatory instincts ignores one half of our ability." Learning should not err on either extreme. It should both provide content of knowledge and develop creative skills to be able to improvise and apply knowledge to new situations.
No matter how a person thinks the human brain developed, Medina's evolutionary model helps us picture what the three basic parts of the brain do. First, we have a "lizard brain," basically our medula, our brain stem. "The brain stem controls most of your body's housekeeping chores" (40), like breathing, heart rate, sleeping, and waking.
Then we have a second brain sitting on top of it, our mammalian or cat brain. It is the seat of our emotions and animal functions like fighting, feeding, fleeing, and reproductive behavior. The amygdala is responsible for emotions and emotional memory. The hippocampus converts short term into long term memory. The thalamus is the "control tower of the senses" (41).
But the human brain overshadowing these other parts is the cortex. It is the part where our ability to fantasize comes from. Humans can uniquely "attribute characteristics and meanings to things that don't actually possess them" (33). Medina draws on "Dual Representation Theory" and actually starts off the chapter with the story of his son treating a stick as a sword (31).
This higher function of our brains allows us to "peer inside somebody's mental life and make predictions" (44). It allows us to pool our strength together in order to survive. That is the title of the chapter, Survival. Rather than evolve stronger, Medina says, we decided to cooperate with each other and face that Wooley Mammoth together (43-44).
Accordingly, relationship is important to learning. In his summary of the chapter, one of Medina's points is that "Symbolic reasoning... may have arisen from our need to understand one another's intentions and motivations, allowing us to coordinate within a group" (47). And as a by-product, poor relationships between teacher and learner can often sabotage learning.
He takes an evolutionary perspective. Humans evolved to move. That's how we survived as a species, he will say in the second chapter. We moved 12 miles a day on average in the early days of our ancestors, he says. It's stupid to cut recess out of public school education, he says. It's like eating less in order to gain weight. I think this is the chapter where he says it cuts the risk of Alzheimers by something like 60%.
His second rule is that the brain evolved too. It's a fascinating chapter. "The brain appears to be designed to (1) solve problems (2) related to surviving (3) in an unstable outdoor environment, and (4) to do so in nearly constant motion" (31-32). It did this so that we could survive long enough to have sex, have children, and live long enough to protect them to grow up to have more sex and children. From a Christian perspective, I might add, it's not a particular grandiose view of humanity, but we are at least this much. We may be more, but we are at least this much.
Later on in the chapter, he has a rather crass, even if possibly accurate sense of how the human womb evolved. The key to the survival of our species, Medina claims, is not that we got stronger but that we got smarter (32, 37). This meant that those with bigger brains--and thus bigger heads--survived more effectively than others. This meant that women with larger wombs survived birth better--and that babies came out sooner. Now parenting and childhood had to take place for years, unlike species where the offspring come out pretty much ready to go.
Medina has a fascinating version of human evolution. We should keep in mind not only that his account may be debatable to some Christians but also among evolutionary experts themselves. Medina traces the key to our evolution to fundamental changes in the earth's weather (35). It knocked our human ancestors out of the trees and onto flat ground that made offspring who stood upright and moved around a lot better suited to survive than those bent over.
Here is one of the take-aways from this chapter. We survived as a species, he says in so many words, because we became a species that improvises and adapts to new environments rather than staying in the same place. We moved out all over the globe and adapted wherever we went. His take-away for learning is something called Variability Selection Theory. Learning is the interaction between two powerful features of the brain: "a database in which to store a fund of knowledge, and the ability to improvise off of that database. One allows us to know when we've made mistakes. The other allows us to learn from them" (37-38).
His conclusion is that "any learning environment that deals with only the database instincts or only the improvisatory instincts ignores one half of our ability." Learning should not err on either extreme. It should both provide content of knowledge and develop creative skills to be able to improvise and apply knowledge to new situations.
No matter how a person thinks the human brain developed, Medina's evolutionary model helps us picture what the three basic parts of the brain do. First, we have a "lizard brain," basically our medula, our brain stem. "The brain stem controls most of your body's housekeeping chores" (40), like breathing, heart rate, sleeping, and waking.
Then we have a second brain sitting on top of it, our mammalian or cat brain. It is the seat of our emotions and animal functions like fighting, feeding, fleeing, and reproductive behavior. The amygdala is responsible for emotions and emotional memory. The hippocampus converts short term into long term memory. The thalamus is the "control tower of the senses" (41).
But the human brain overshadowing these other parts is the cortex. It is the part where our ability to fantasize comes from. Humans can uniquely "attribute characteristics and meanings to things that don't actually possess them" (33). Medina draws on "Dual Representation Theory" and actually starts off the chapter with the story of his son treating a stick as a sword (31).
This higher function of our brains allows us to "peer inside somebody's mental life and make predictions" (44). It allows us to pool our strength together in order to survive. That is the title of the chapter, Survival. Rather than evolve stronger, Medina says, we decided to cooperate with each other and face that Wooley Mammoth together (43-44).
Accordingly, relationship is important to learning. In his summary of the chapter, one of Medina's points is that "Symbolic reasoning... may have arisen from our need to understand one another's intentions and motivations, allowing us to coordinate within a group" (47). And as a by-product, poor relationships between teacher and learner can often sabotage learning.
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