Category Archives: Mysteries of the Brain

MYSTERIES OF THE BRAIN Part 26: Why is a smaller chimp much stronger than a larger human?


This is episode no 26 of the VERITAS series on the mysteries of the brain. Older parts can be found here:

Chimpanzees are the closest living relatives of humans. The genetic difference between humans and chimpanzees is less than 2%. But the strange thing is that chimpanzees are much stronger than humans. Some scientists have done experiments that show that an average chimp is 8 times stronger than a human. Others estimate that the difference is between 2 to 5 times. These experiments were done using pulling and lifting weights. So chimps can pull or lift many times more weight than humans. And in a human-chimp fight, the human would be massacred. There have been reports of a small chimp nearly killing a much bigger human. So an average chimp is many times stronger than an average human. This is remarkable especially given the fact that an average chimp is much smaller in size when compared with an average man. A male chimp is about 5’3 inch tall and weighs between 40 and 60 kg. So how is it that a much smaller animal is so much stronger than us humans? And why are we discussing this in a VERITAS series on the mysteries of the human brain? Well, you will find the answer to both these questions below.

The difference between a human and a chimp’s strength does not lie in the muscles. The difference lies in the way the nervous system controls the muscles of these two creatures.  To understand this first we need to know about grey matter and motor neurons. Grey matter is a major component of our central nervous system. The grey matter includes the regions of the brain and spinal cord responsible for muscle control, speech, hearing, emotions and decision making. The motor neurons originate from the gray matter located in the spinal cord and connect to the muscle fibers in our limbs. The signals are sent by the brain/spinal cord through the motor neurons and they move the muscles which are connected to them. Now, there are two kinds of motor neurons- some motor neurons are connected to many muscles forming what is called a large motor unit. Other motor neurons are connected to a few muscles and these form the small motor unit.

So if I need to jump, climb a tree or lift a heavy weight, the large motor unit comes into play and many muscles are moved by a single “command” passed through a motor neuron. But if I need to hold a pen, draw a picture or use chopsticks to eat noodles, it is the small motor unit that becomes active- only a few muscles are contracted.

Another way to look at this is that large motor unit lets us do tasks that involve power and strength. On the other hand, small motor unit allows us to do delicate, precise tasks.

Now, lets come back to chimps and humans. Chimps have much less grey matter and this means that they have less motor neurons. Therefore each motor neuron is connected to many muscles creating large motor units. So most muscles in a chimp are parts of large motor units. This enables them to run, climb and lift heavy weights. On the other hand, humans have a lot more small motor units. Most of our neurons control smaller sets of muscles allowing us to do specific tasks- we can write, we can play musical instruments, we can type!

In summary, the reason why chimps have greater “raw” strength is because their nervous system has less fine motor control. What this means is that the neurons of a chimp cannot pick and choose a few muscles at one time.

So we see that strength does not just depend on how many muscles a creature has. A chimp may have less muscles but has more muscles employed for “power” tasks like climbing, running and lifting and very few employed for delicate/specific tasks. In the case of humans it is the opposite.

Raw strength is not what humans are good at. Our thousands of years of evolution from our ape ancestors has not been in a direction that enhances our ability to employ power. Instead, we have become more mental creatures and our muscles let us do more complex tasks to bring our compex ideas into a physical form. Our strength is not in things like running or lifting. Our “strength” is in activities like calligraphy and using sophisticated tools.


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Go wondrous creature, mount where science guides

go measure earth, weigh air, state the tides,

instruct the planets in what orbs to run

correct old time, regulate the sun

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MYSTERIES OF THE BRAIN Part 25: What was the catalyst for the extraordinary evolution of our brains?


This is episode no 25 of the VERITAS series on the mysteries of the brain. Older parts can be found here:

In this part we will learn about a very important event that resulted in the remarkable development of the human brain. And it is this event that resulted in humans becoming so much more intelligent than other creatures which in turn has made us the dominant species on earth.

The question that we must answer first is this: if intelligence is good and if intelligence has an evolutionary advantage then why don’t we see all animals grow massive brains? I must tell you that there are some animals like bats whose brain sizes have decreased with time. The answer is simple: Brains are costly. When I say costly, I mean costly in terms of energy consumption. In bats the competition was between maintaining or growing a costly brain vs  the energy cost of flying. Evolution decided that flying is more important for bats in terms of ability to survive so brain sizes went down and precious energy resources were used for flying.

Therefore the  size of the brain is governed by the constant battle for energy. If a creature does not need a bigger brain for survival or does not have enough food to  supply the energy required by a bigger brain, then the brain size would not increase.

Now let’s answer the question: how much energy does a brain consume? Most animals have brains that take up 2% to 8% of their total metabolism. In human brains the percentage is much higher. An average human brain requires 20 to 25% of the total energy requirement of our bodies. So nearly 25% of the energy that we consume goes to our brains! This energy requirement is even more remarkable when we consider the weight of the brain- only 2% of our body. So the human brain is 2% in weight  but consumes 25% of the energy that our body consumes.

So if we make the statement that our brains are large because we have enough food to feed its energy requirement, we would not be wrong. But there is a deeper mystery. We have more food because our intelligence has enabled us to get surplus food. There was a time in history when we too lived in jungles like other animals and that time we too struggled for energy. So what caused our brains to grow? And to give you an indication of the growth: the human brain weight was about 400 gms about 3 million years ago- this is comparable to modern chimpanzees. Today the brain size of an average adult is about 1400 gms. So the question is : how did we manage to solve the energy problem required for a bigger brain? What is it that gave our ancestors the ability to get more energy thus causing rapid brain size increase?

The answer is simple: cooking. Our ancestors discovered fire nearly two million years ago and that suddenly changed the trajectory of the “human” race. Today we cannot eat most of our food raw and unprocessed. We do many things to it: we pound it, we grind it, we ferment it, we cook it. And all these things that we do to food improves the efficiency of energy that we extract from it. For example grinding and pounding makes the food particles smaller and it becomes easier for our stomachs to digest the food. However the biggest impact on energy efficiency came from cooking. A group of scientists did some experiments on mice. They divided mice into two groups- one group was given raw potatoes and the other was given the same quantity of cooked potatoes. After four days the scientists found that the mice that had been eating raw food lost on an average 4 grams . The group of mice that ate cooked food gained weight.

Cooking food breaks it down and makes it easier to digest – less energy is expended in digesting this food. In scientific terms, cooking causes a denaturation of proteins which causes some of its structures to break down and therefore more easier to digest.  Also since the food is digested better, we are able to get more energy from it. In addition, cooking kills germs and less energy is used by the immune system to kill the incoming germs. And as humans started eating cooked food, our guts started decreasing in size. So we saved the energy required to maintain a bigger gut. All these energy savings and the extra energy from cooked food meant one thing- we had an energy surplus. We could afford a bigger brain. And that is what we have now. We have probably the most expensive brain in the animal kingdom – one that uses 25% of our incoming energy.  But that’s okay because we have that extra energy to spare because of cooked food.

Cooking also had another effect that contributed to our rise. We wasted less time in eating. A giant panda spends upto 16 hours a day chewing bamboo. The panda nearly never eats anything else but the food that it eats is so difficult to digest that it has to spend every waking hour eating. It has no time for anything else. Pandas are not very social creature because even being social is time consuming and energy consuming. And the panda has no time to waste- it has to keep chewing all day to maintain its weight. Our primate cousins – chimps also spend nearly half a day eating food. Eating low calorie density food like fruits and bamboo shoots means that the creature has to eat for more time in the day. Carnivorous animals do better and have time to spare but not so much. Cooking gave us the advantage that we had free time for other things. An adult human spends only about an hour eating food in a day. And we are still able to feed our massive brains sufficiently. In fact the efficiency of our cooked food is so high that we are able to gain weight by eating only an hour in a day and even after feeding 25% to our brains.

Now let’s take a different view of the cooking theory. If you want to decrease weight you should be eating more of raw food or at least lesser processed food. Some studies have suggested that people who eat raw foods or unprocessed food ( like whole wheat bread etc) spend two times more energy in digestion as compared to people who only eat processed, cooked food. Also you will get less energy from raw food. So eat raw food if you want to decrease the energy consumed from food. However, do not apply this theory on kids. They need energy so cooked food is actually much better for them.

So the discovery of fire resulted in the extraordinary evolution of the human brain.

If you want to know more about the cooking hypothesis read the book “Catching Fire, How cooking made us human” by Richard Wrangham.

And to make your day( and mine) even more delicious here are some excerpts from a poem by Ogden Nash:

Some singers sing of ladies’ eyes,
And some of ladies lips,
Refined ones praise their ladylike ways,
And course ones hymn their hips.
The Oxford Book of English Verse
Is lush with lyrics tender;
A poet, I guess, is more or less
Preoccupied with gender.
Yet I, though custom call me crude,
Prefer to sing in praise of food.
Yes, food,
Just any old kind of food.
Some painters paint the sapphire sea,
And some the gathering storm.
Others portray young lambs at play,
But most, the female form.
“Twas trite in that primeval dawn
When painting got its start,
That a lady with her garments on
Is Life, but is she Art?
By undraped nymphs
I am not wooed;
I’d rather painters painted food.
Just food,
Just any old kind of food.


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Go wondrous creature, mount where science guides
go measure earth, weigh air, state the tides,
instruct the planets in what orbs to run
correct old time, regulate the sun
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MYSTERIES OF THE BRAIN Part 24: Face Recognition and Face blindness

As was with many of the earlier parts of this series, we will start by describing a mental condition or disease. The reason is that mental illnesses give us a great insight into how the brain functions. When neurologists analyze mental illnesses they understand what parts of the brain are involved in different cognitive functions and how specialized different parts of the brain can be.

Today our topic of discussion is face recognition. Face recognition is very different from recognizing other objects. This fact is illustrated by the mental disorder named Prosopagnosia. The word Prosopagnosia comes to us from two Greek words: prosopon( face) and agnosia( not knowing). A person suffering from this disease is able to recognize objects and his intellectual abilities are normal however such a person has difficulty in recognizing faces. So from this we condition we understand that face recognition is a very specialized task and different from recognizing other objects around us.

Recognizing faces and understanding the emotional content of faces is extremely important for social behavior. A child as young as two days old looks at faces carefully and tries to mimic the expressions on others. However at that age he/she is not able to judge the emotional messages that are encoded in these expressions. By the age of 5-7 months a child is able to distinguish between expressions of fear, happiness and anger when he sees the faces of people around him/her.

Scientists have a way of finding out which part of the brain is used for which function. It is called fMRI or functional Magnetic Resonance Imaging . This method detects changes in blood flow to different areas of the brain to find out which area is responsible for what function. When a set of subjects were shown faces and cars scientists found that a certain area of the brain known as fusiform showed much higher levels of activity when the subjects viewed faces than when they viewed cars. This area is now known as fusiform brain area and we know that it specializes in recognition of faces. Recognition of other objects ( not faces) happens using a different mechanism and is not specialized.

So the fusiform brain area is very active when we see faces but not active when we see cars or say birds. But a group of scientists did another extremely interesting experiment. They took a group of people who were expert bird-watchers. When these people were shown different birds their fusiform brain areas showed a very high level of activity- similar to normal people viewing faces. So the theory is that when we see something that we are extremely interested in, or experts in, the fusiform brain area is triggered. So another way of looking at it is that we are all experts at and extremely interested in face recognition.

Now let’s discuss Prosopagnosia. If the fusiform face area is damaged the person loses the specialized ability to recognize faces. But he is able to recognize other objects like the rest of us. So a person with this condition recognizes faces the way we recognize other inanimate objects around us and therefore the person is not able to do it very well. Children with Prosopagnosia are extremely shy because they are not able to recognize people easily. So they tend to make friends with children with easily distinguishable features( like distinct colour of eyes or a scar on face etc).

In face perception, race can also play a role. If a person does not have contact with people from other races, he tends to think that all of them look alike. This is called the cross-race effect. In experiments scientists found that when a person was shown images of people from other races, the motivation to differentiate based on facial expression decreased subconsciously thus decreasing the ability of a proper facial recognition. In an experiment a set of store counter clerks were asked to recognize people who came to their shops to purchase goods. They tended to do very well at recognizing people from their own race but people from other races all seemed to “look alike”. However if a person from one race is constantly in contact with people from other races, the ability to do a proper facial recognition increases. In a very interesting study, scientists found that the cross-race effect decreases after subjects consume alcohol. So maybe alcohol is the best way to ensure global peace and brotherhood 

Face recognition also has a conscious and unconscious component. People with Prosopagnosia were shown pictures of people within their families and also pictures of completely unfamiliar people. As expected the subjects could not recognize any of them however when the conductivity of their skin was measured, there was a great difference between the readings when seeing “known” people and unknown people. So even though there was no conscious recognition of the faces, there was a subconscious emotional response on seeing the people “known” to them. In a “Mysteries of the Brain” series VERITAS posted in 2005 we had discussed a condition known as Capgras Syndrome( A person suffering from Capgras syndrome can recognize people but feels no emotional response to them. So for example when a person suffering from Capgras syndrome meets his mother, he recognizes her but feels no emotions. In fact he may think that she is some other woman who looks exactly like his mother. So this inversion of emotions and recognition indicates that Capgras syndrome is the inverse( or reverse) of Prosopagnosia.

Another very interesting effect related to face recognition is known as the Thatcher effect or illusion. Imagine that you are shown two pictures of a face: one picture is upright and the inverted. Now an identical change is made in the two pictures. You would immediately be able to find the difference in the upright image but recognizing the change in the inverted image would be much more difficult. So when we process an upright face we use the efficient face recognition system but when we see the image of an inverted face, we try to recognize it like any other object which does not employ the efficient face recognition system( fusiform area). A person with Prosopagnosia does not show the Thatcher effect because for him both the upright and inverted faces are “normal” images that are recognized/perceived in a similar way without using the fusiform area. This effect is known as Thatcher effect because it was first demonstrated using the image of Margaret Thatcher. For some very amazing ( and shocking ) images of Thatcher effect see : and

So we see how complex and interesting our brain is. We humans needed a way to process faces efficiently to perceive even the minutest emotional signals in the faces of people around us and to be able to recognize the people that we know really fast, and evolution gave us a dedicated face processing unit. Fantastic isn’t it?

How can we end a VERITAS devoted to faces without some face poetry which is of course inspired by beautiful faces 🙂

Give me a look, give me a face,
That makes simplicity a grace;
Robes loosely flowing, hair as free,–
Such sweet neglect more taketh me
Than all the adulteries of art:
They strike mine eyes, but not my heart.
— Ben Jonson


Go wondrous creature, mount where science guides
go measure earth, weigh air, state the tides,
instruct the planets in what orbs to run
correct old time, regulate the sun

MYSTERIES OF THE BRAIN Part 23: What size is the moon?

Curious friends,

                Lets start with one of my favourite poems: “To the Moon” by Shelley

     Art thou pale for weariness

       Of climbing heaven, and gazing on the earth

       Wandering companionless

       Among the stars that have a different birth,-

       And ever-changing, like a joyless eye

       That finds no object worth its constancy?


                We have all noticed that the moon appears larger near the horizon and smaller when it is high in the sky. In this short VERITAS, I will talk about the reason for this phenomenon.

                The ancient Greeks had observed this and Aristotle had tried to explain this in terms of refraction and magnification caused by the Earth’s atmosphere. However the problem with the Greeks was that they never bothered experimenting. They would just make a theory and then assume that it is correct.

                In the 11th century the Arab/Persian scientist Ibn al-Haytham did a huge number of experiments on light and how we see. He wrote his findings in the “Book of Optics”( Kitab al-Manazir). Some scientists consider this one of the most influential books in the history of Physics along with Newton’s Principia Mathematica. This book set optics on a firm scientific foundation. The book studied reflection, refraction, visual perception, how the eye works. There is even a description of the pinhole camera! Al-Haytham even noted that the speed of light is finite and the speed changes in different mediums. He was also the first to apply geometry to the study of light forming the subject of geometrical optics. This book influenced a lot of research on light and its properties in renaissance Europe several centuries later.

                Ibn Al-Haytham also observed that the moon appears much bigger near the horizon and smaller high in the sky. He knew Aristotle’s theory also. Al-Haytham was a real scientist and experimented and immediately found that Aristotle was wrong. Using experiments and geometry Al-Haytham was able to show that if atmospheric refraction/magnification were to be taken into account, then the moon high in the sky would appear slightly larger than the moon at the horizon. However the moon at the horizon appears larger. So atmospheric refraction cannot explain this. Aristotle was wrong( as he has been on so many other occasions as well).

                Al-Haytham did many more experiments and geometrical calculations before coming to the conclusion that this phenomenon is actually an illusion! The brain is playing tricks on us. Al-Haytham was also the first to explain how or why this illusion actually occurs.

                You can yourself verify that this is an illusion by taking pictures of the moon at the horizon and high in the sky. They will have the same diameter!

                When we look at an object at a distance, it appears smaller but our brain knows that it distant and that is why it appears small. Our brain can judge the size of the object by judging its distance. That is how artists give an impression of distance on a flat canvas: as things move away, they appear smaller. This is called Linear Perspective. And in our minds the horizon is always a distant place. We see a mountain that appears so small at the horizon but our brain knows that it is much larger than it appears. Now the moon is at equal distance whether it is high in the sky or at the horizon. But our brain thinks that since it is at the horizon it is much farther away and it should be larger than it appears. So the brain compensates and makes the moon look bigger than it is.

                Note that the above is just one possible explanation of the moon illusion. There are more. Many more. There is a book on the Moon illusion in which 24 chapters are written by 24 different illusion researchers and they do not agree with each other. So this is not a closed topic!

                Another explanation is that when the moon is high in the sky there are no other objects to compare its size against. When it is at the horizon there are many things that we can compare against: the trees, the mountains, the houses and the image of the moon is bigger at the horizon than any of these objects. The human mind bases a lot of its perception on comparison. A thing placed next to larger thing appears smaller than it really is. However if the same object was placed with smaller things, it would appear bigger. The brain compares the size of the moon at the horizon with the distant and small objects at the horizon and gives us the impression that the moon is larger.

                There are more explanations as well. You can find them on the internet. Ibn Al-Haytham did a lot of experiments on illusions. In fact he was the first to show/suggest that the eye is just the place where the image is formed. The ultimate perception of seeing takes place in the brain.

                Now, you may ask, why is this still a open topic even a 1000 years after Al-Haytham first suggested that it is an illusion. Why are different theories of how this illusion works still around and there is no one explanation? The answer is simple: the illusion is not something that we can recreate outside the brain. The illusion is in the brain, caused by the brain. And what goes inside the brain is still an unsolved mystery. See the rest of the VERITAS articles on the mysteries of the brain at: VERITAS blog site(  Look at the “Mysteries of the Brain” tag).


Let me now end this VERITAS just as I started it: with a poem. This one is by Robert Frost:

I stole forth dimly in the dripping pause

Between two downpours to see what there was.

And a masked moon had spread down compass rays

To a cone mountain in the midnight haze,

As if the final estimate were hers,

And as it measured in her calipers,

The mountain stood exalted in its place.

So love will take between the hands a face….





Go wondrous creature, mount where science guides

go measure earth, weigh air, state the tides,

instruct the planets in what orbs to run

correct old time, regulate the sun


MYSTERIES OF THE BRAIN Part 22: Classical conditioning and beyond

Veritas Readers,


                This is the 22nd part of The “Mysteries of the Brain” series.  All earlier episodes are available on the VERITAS blog site(  Look at the “Mysteries of the Brain” tag).

                Most of us have read or heard about Pavlov conditioning. However there are some lesser known experiments that he did and these experiments give some very interesting insights as to how our mind works. In this VERITAS we will study Pavlov’s experiments and their very interesting insights.

                Ivan Petrovich Pavlov was not really researching about how the brain works. He was more interested in digestion. In the 1890s he was doing experiments on digestion using dogs at the university of Saint Petersburg. He observed that the dogs started salivating whenever they saw the lab technician who usually fed them even if he arrived without any food. Pavlov wanted to understand this association and devised a series of experiments which hugely increased our understanding about our minds and our behavior.

                Pavlov started preceding the feeding of the dogs by the ringing of a bell. So first a bell rang and a few moments later the dogs were given food. After a few days of doing this Pavlov saw that the dogs started salivating as soon as they heard the bell. So the dogs had formed an association between the bell and the food. After a few days the bell was sounded without the food being given immediately afterwards. But the dogs continued to salivate at the sound of the bell. So the bell that now had nothing to do with food still triggered a salivating response in the dogs. This phenomenon is called conditioning( some people call it classical conditioning or Pavlov conditioning). Note that this is an subconscious effect.

                A few technical terms to help you understand other articles on Pavlovian conditioning using the above example

1)      Food: Unconditioned stimulus

2)      Salivation on seeing food: unconditioned response

3)      Bell: First this is a neutral object but after  the dog makes an association between the bell and the food this becomes conditioned stimulus.

4)      Salivation on hearing the bell: Conditioned response. This is not a natural response but has been learnt by association.

                A lot of our behavior is based on Pavlov conditioning. Sometimes a particular song may take you into a different time and induce a mood that you felt when you had  heard that song in the past. Let’s take the example of mathematics. We have millions of people with a fear of mathematics even in adulthood. Why? Because mathematics is associated in childhood with unpleasant feelings of fear, worry, and lowering of self esteem by “not-so-well-versed in psychology” teachers and parents. Let’s take another example: young children who suffer from cancer are sometimes given an ice cream before chemotherapy as a reward for agreeing to undergo the painful experience. Now chemotherapy induces nausea. Even when such a child grows up the association between ice cream and nausea remains causing them to feel sick even at the sight or smell of ice cream.

                Pavlov conditioning is a very powerful effect and can have a permanent effect on a person’s brain. Its proper use can be used to improve education in our schools. Of course, schools sometimes(!) end up accidently using it in a negative manner causing kids to hate studies. Pavlov conditioning has been used to cure phobias and in behavior therapy of criminals. In case of criminals, Pavlov conditioning is used to associate physical discomfort with their criminal thoughts. For example sexually deviant people are made to smell unpleasant substances when they are describing their deviant fantasies. This causes a permanent aversion to whatever they were thinking. Such methods have, in recent years come under attack from rights activists.

                Now let me describe a lesser known but very interesting experiment conducted by Pavlov. Before we proceed further I must stress once again that conditioned response comes from the subconscious. The conscious brain has no control on it. Pavlov showed some images to the dogs: whenever he showed the image of a circle it was followed by food. When the image shown was an ellipse, the dogs were given a small electric shock afterwards.  The dogs quickly learned to differentiate between the two images. When the image of the circle was shown, the dogs would start salivating and wag their tails. When the image of the ellipse was shown, the dogs would start whining and would try to run away. After a few days of doing this, Pavlov decreased the eccentricity of the ellipse( made it less longer and more circular) by a small amount. The dogs had no problem differentiating between the ellipse and the circle and the respective reactions to seeing them stayed. Pavlov continued to decrease the eccentricity of the ellipse but the dogs continued to differentiate the ellipse from the circle and their reaction of fear at seeing the ellipse and salivating when seeing the circle continued. However when the eccentricity of the ellipse was made about 9:8( nearly a circle but not exactly) the dogs were not able to differentiate- and their reactions suddenly became completely unpredictable and weird. They did not know how to react. They became very anxious and would whine and even defecate on seeing the image. And they now gave the same reaction on seeing the circles. Some of them became so disturbed to see the circle or ellipse they had a nervous breakdown. So the dogs had the nervous breakdown because they were no longer able to differentiate a happy stimulus from an unhappy one and their subconscious minds did not know how to react. Thus when the subconscious mind experiences a conflict that it cannot resolve, it causes anxiety, nervousness and at times even mental breakdown. Note that after showing the ellipses of 9:8 eccentricity, the dogs lost all differentiation of even normal circles and ellipses. The earlier conditioning was lost and a new behavior of mental disturbance set in.

                Pavlov now tried to train the dogs to differentiate the circles from the ellipses again. Once again he started using normal eccentricity ellipses and followed them with electric shocks, and he used images of circles and followed their images with food. This time the dogs had a much more difficult time learning how to differentiate between ellipses and circles compared to the first time. So he observed that once the differentiation was lost, it was difficult to create again. So in a sense the dogs had become less sensitive to external stimulus. These experiments show us that there is a difference between the first experience of something and subsequent experiences- the first experience will always make the mind condition to the stimulus much faster and better than subsequent experiences.

                Based on Pavlov’s findings, Eysenck formed his theory of extroversion and introversion. An introvert is more sensitive to external stimulus and easily conditioned. An extrovert is less sensitive and his subconscious brain is more difficult to condition. The reason for extroversion may be natural or acquired- maybe that person has been through that experience earlier and similar experiences do not cause the same conditioning and differentiation- much like Pavlov’s dogs shown the circles and ellipses after they had lost the differentiation.

                I think Pavlov’s experiments tell us a lot about how we learn things and how experience the world around us.  I don’t think we really understand how we can apply classical conditioning to enhance the learning experience of students and make studies less stressful and confusing. Also classical conditioning can give us extremely important insights into why people behave the way that they do and how socially beneficial behavior can be learnt not just by individuals but also by the whole society if we think of society as a collective conscience.

Pavlov received the Nobel Prize in 1904. But that was not for his contributions to psychology- that was for his studies on the digestive system.  

                After Pavlov’s experiments, a lot of psychologists started thinking about conditioning and its impact on behavior. They began to expand the scope of conditioning beyond classical conditioning. In general, Conditioning is an learnt association of things with each other at a subconscious level. When I say learnt I mean that this association is not natural but is acquired by a constant association which we experience in our lives. We have studied Classical conditioning. Now lets briefly look at Evaluative conditioning and social conditioning.

                Evaluative conditioning is the association of likes or dislike towards something related to something else that you may like or dislike. Lets take an example: if we strongly dislike someone say A . And a different person, B always is found with A, then we may start disliking B as well. This kind of conditioning is the basis of a lot of advertisements. You may like a celebrity and if he or she appears to like a product, you will start associating that celebrity’s characteristics with that product and will start liking it. That is why advertisers are very conscious about the brand value of celebrities. When a celebrity gets involved with a controversy( as they so often do), suddenly they start getting less advertisements.

                A very interesting experiment demonstrating evaluative conditioning was done some years back: a set of people were treated to a delicious free lunch and during the course of the lunch, a set of political slogans were shown to them. Another set of people were taken to a room filled with bad odours, and in the room they were shown the same political slogans. It was found that the free lunch subjects had a much more favourable opinion of the slogans compared to the people who saw the slogans in the bad odour filled room. This is evaluative conditioning.

                Another example which I am sure a lot of you would be familiar with. Sometimes during the naming of a new born child, parents tend to disagree with each other a lot on the choice of names. Why? Because they have associated names with characteristics of people who had those names! A husband may have had a favourite teacher named Suresh in childhood. So for him the name Suresh stands for love for knowledge, patience and kindness. However the wife may have met a uncouth, ill-mannered person named Suresh. And for her Suresh is a very bad name for a child. This is conditioning. Remember, all this is happening at a sub-conscious level!

                Now, lets talk about social conditioning. Society tends to favour certain behaviours and disapprove others. This causes a subconscious conditioning in the minds of individuals who grow up in that society. It may be related to what choice of professions are “better”,  what “kind of people” are to be liked or disliked. Even, the concept of physical beauty is related to social conditioning. The society floods us with images and messages of what is beauty and what is not. And people’s minds get conditioned to it. For example, why do Indians associate fairness with beauty? Social conditioning. Come to think of it, even patriotism is an example of social conditioning. Why should your love for humanity stop at the border? Because society wants you to think that the people on this side are our people and the people on the other side of that artificial line side are not ours- and not so nice. Social conditioning.



Go wondrous creature, mount where science guides

go measure earth, weigh air, state the tides,

instruct the planets in what orbs to run

correct old time, regulate the sun


Mysteries of the brain – Part 21 : Visual Consciousness



            This is going to be a very short VERITAS mail. There is something incredibly interesting that I read yesterday and I really wanted to share that with people.

            There is a huge amount of external stimulus that reaches our senses every second. It is estimated that about 10 billion bits(10,000,000,000) of visual information reaches our eyes every second. But the eye has its limits. The optic nerve at the back of the retina can transport only 6 million(6,000,000) bits per second to the brain. The visual cortex in the brain processes only about 10,000 bits per second.
And the no of bits that go to form the conscious awareness of what is being seen is only 100 bits per second.

So though we are able to see 10 billion bits every second through our eyes, our perception of what is being seen is formed by only about 100 bits per second: an insignificant amount of information! So the perception of reality is only triggered by the external stimulus: most of it is formed within the brain. We see a little and we make up a huge amount. This is related to  what Aakanksha told us in :
“VERITAS: Mysteries of the Brain Part 20: Hypnosis”

This applies to all senses. We take very little from the outside word- we make up most of our perceived reality. 
John Milton said ” The mind is its own place, and in itself, can make heaven of Hell, and a hell of Heaven.”


Go, wondrous creature! mount where Science guides:
Go, measure earth, weigh air, and state the tides:
Instruct the planets in what orbs to run,
Correct old time and regulate the Sun;

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Mysteries of the Brain Part – 19 – GENIUS


Do geniuses have a different brain than the rest of us? Are their brains bigger?
Or do their brains have more neurons? We will answer these questions in today’s VERITAS.
And to help us answer these questions we have perhaps the smartest brain of all: Einstein’s brain.

 Ask anyone around you: who do you think was the most intelligent person ever? I bet more than 80% people will say Albert Einstein. Most people do not know what he really did but he has become the icon of genius for the modern world.

 When Einstein died in 1955 his brain was taken out by Thomas Harvey who performed Einstein’s autopsy. The brain was photographed and preserved for scientific research into the nature of genius. Harvey also weighed the brain. It was a modest 2.6 pounds. So Einstein’s brain was just of average size and weight. Harvey did take out Einstein’s brain for scientific study but he refused to part with it afterwards. He was removed from his job for not giving the brain to the hospital where he was working. It was only in 1970s that Harvey entertained requests by scientists to give them samples of Einstein’s brain.

 The brain of the great mathematician Karl Fredrich Gauss has also been studied by scientists and they have found nothing special in that. But Einstein’s brain received a special treatment from scientists who have devoted decades of research to find that one thing that we can identify
with his exceptional intelligence.

 In 1970s researchers working on mice found that the mice that lived in more mentally stimulating environments have more glial cells per neuron then mice that lived in less mentally challenging environments. Glial cells are the support cells for neurons. Glial cells are created and destroyed
throughout the individual’s life( neurons do not increase in number by more than a small amount). Glial cells provide nutrition, hold the neurons in place by forming a sort of glue and they also modulate neurotransmission.

 In the 1980s scientists found that Einstein’s brain had a much larger concentration of glial cells in one part of the brain- the Broadmann area no 39. This part of the brain is responsible for synthesizing information from several brain functions.

 In 1999 another set of scientists noticed some strange anatomical features in Einstein’s brain. Two features of the brain were missing:

1) The operculum region in the frontal lobe of the brain: This part plays an important role in speech production. It is well known that Einstein started speaking very late- his speech was unclear   even at the age of 9 years.

2) Sylvian fissure: This divides the frontal lobe and the parietal lobe. In Einstein’s brain there is no such division. Scientists have proposed that this may have resulted in a better communication between neurons of the frontal lobe and the parietal lobe.

 Also because of the operculum region not being there another part of the brain compensated and became 15% larger than normal: the inferior parietal lobe. And this part is responsible for mathematical thought and visual-spatial imagination. So the mathematical part of the brain developed at the cost of the part of the brain responsible for speech.

 So do these anatomical differences and glial cell numbers tell us why Einstein was a genius. We do not know for sure. We can only know when we have studied the brains of a lot of geniuses. If anatomical abnormalities cause a genius like Einstein then I would be very disappointed. It should not take an abnormal brain to create the theory of relativity. Genius should be the product of the love for knowledge and the ability to play with ideas.  I tend to agree more with Thomas Carlyle’s statement:

       ” Genius is the transcendent capacity of taking trouble”



Go, wondrous creature! mount where Science guides:
Go, measure earth, weigh air, and state the tides:
Instruct the planets in what orbs to run,
Correct old time and regulate the Sun;

Mysteries of the Brain Part – 18 – TRUST


In this episode of the series we explore how and why we trust other people. What brain processes are involved in the social interaction of trust? Is there a hormone that is responsible for trust? We will study all this today. This VERITAS article is based on a Scientific American magazine article in the June edition of the magazine.

Human society is what it is today because we tend to trust each other- we even trust the people we do not know. If you go to a new city and ask for directions you are reasonably certain that the directions given by strangers on the street will be correct. We tend to trust each other except
in some very specific situations.

All animals, even less developed ones like fish and lizards display trust in atleast one interaction: sex. All sexually reproducing animals display this trust. The females of any species will let a male approach her when she is ovulating because the benefits of sex( offspring and genetic diversity) overweigh the danger of being harmed( or even eaten) by the male of the species. Scientists have found that in fish the release of
the hormone vasotocin reduces the female’s fear of being approached by a male when she is ovulation. Thus the trust displayed by a female fish on a male fish for sex is due to the hormone vasotocin.

In mammals the hormone oxytocin plays a huge role in female reproduction: from sex to labor to lactation. And Scientists have found that this hormone is responsible for all social interactions involving trust. So the complex trust that we humans exhibit on each other seems to have evolved from the trust that even simple creatures display during sex. And this trust is also due to a hormone in the blood-oxytocin.

To test their theory about the role of oxytocin in trust Scientists devised a “trust game”. They asked people to volunteer promising them 10$ if they play the game. In any game session two people played the game: let’s call them A and B. A and B did not know each other and they do not meet during or after the game. The game gives A 10$ and B 10$. Now A can give B some of his 10$. Let’s say he gives B x dollars. If that
happens then B will get his 10$ plus 3 times the amount that A gives him. So if A gives B 6 dollars then B gets 10$ + 6 X 3 = 28$. Now B can return some of the money that he made to A to thank him for making that extra money. But if A does not want to give any money to B he is not forced to do it- he can display a non-trusting behavior: what happens if I give money to B and he makes the extra money but does not give me
back any of it. Similarly B can act selfish: he can keep all the money without giving anything back to A.

The Scientists played this game with several sets of players and found that 85% of the ‘A’ people gave some of their money to B. And 98% of the “B” players went on to return some of their money to A. The researchers found that B players with higher levels of oxytocin returned higher amounts of money to the A players. These B players responded more positively to the trust placed on them by their A counterparts.

The researchers also calculated the change in oxytocin levels in B subjects when they got some money from A. If the A player sent more money to B the oxytocin level in the B players increased more compared to when less money was sent by A. So your oxytocin level increases when someone displays trust in you and since now you have more oxytocin level you tend to respond to the trust in a more positive way: you act more trustworthy!

And then the researchers went on to consider how our hormone levels change when someone displays distrust in us. And here there is a difference between males and females. If during the trust game a player A did not give any money or very little money to a male player B his(B’s) DTH( dihydrotestosterone) levels would increase. DTH is responsible for violent  behaviour in males. So when a male is distrusted he tends to exhibit a violent behavior.  However if a female B player did not get any money from A she would simply not return any. And if she received a small amount from A she will return a small amount back. There will be no change in her DTH levels but she does respond with : ” you gave me little so I will return little” approach.

The article says that our oxytocin levels may vary minute by minute and over our entire lifespan. And life experiences may retune the base oxytocin levels to a different level thus making us generally more trusting or less trusting.

This indeed is a very interesting study and something that paves the way for treating the hatred and distrust that exists in our society for people who follow different religions or are from different societies or countries. And one thing is for certain: if you place trust in someone his desire to become trustworthy increases. This is the moral of the story for me.



Go, wondrous creature! mount where Science guides:
Go, measure earth, weigh air, and state the tides:
Instruct the planets in what orbs to run,
Correct old time and regulate the Sun;

Mysteries of the Brain Part – 17 – SLEEPWALKING


This post was written on Thursday, August 09, 2007

A few days back a friend of mine told me that her brother sleepwalks. That got me curious about sleepwalking and its reason. I have also sleepwalked once when I was about fourteen years old- I slept in my room and in the morning I found myself sleeping on my parents’ bed in the adjacent room. I have never sleepwalked after that. In today’s VERITAS we will try to understand this phenomenon.


In medical language sleepwalking is called somnambulism( somn is sleep, ambulism is to move). People are said to sleepwalk when they move around in their sleep or do other actions in their sleep which are normally done by fully awake people. So a sleepwalker may walk around his house while sleeping. Or a sleepwalker may clean the floor or talk or climb stairs during their sleep. Some people have been known to do extremely complicated tasks like driving during their sleep. And there are even cases where murders have been committed during sleepwalking and there is a bizarre case in which a woman had sex with strangers during her sleep! So it is a very complicated behavior!


And sleepwalking is not uncommon at all. About 18% of the population is prone to sleepwalking- i.e. about 1 in 5 people have sleepwalked at least once in their lives! But only 3-6% of the people sleepwalk more than once or twice. Children and adolescents are much more likely to sleepwalk as compared to adults. And males are more likely to sleepwalk than females.


A lot of sleepwalking goes unnoticed because the most common form of somnambulism is not walking in sleep. Most sleepwalkers just get up while sleeping, look around with open eyes, close eyes again and lie down. So people around  such sleepwalkers may never notice.


Most movies depict sleepwalkers as moving around with eyes closed and arms outstretched. But this is not the case. Sleepwalkers move around with their eyes open. They are able to navigate their way using visual clues. It is just that their brain sleeps while their bodies are awake! Sleepwalkers have a blank look in their eyes while they sleepwalk. They can even answer simple questions but they cannot make complex decisions. So there is always a danger that the sleepwalker may hurt himself during sleepwalking. There are cases when sleepwalkers have fallen down stairs or cut themselves while doing complex tasks during sleep.


It is commonly thought that sleepwalkers should not be woken up while sleepwalking. This is not dangerous at all. You can wake up a sleepwalker but he will be extremely surprised. Sleepwalkers never remember what they did during sleepwalking.


Most people think that sleepwalkers are acting out their dreams. But this also is not true. We have seen in an earlier
VERITAS that sleep has various stages( see VERITAS: Mysteries of the Brain part 14, 19th May 2006):


1) stage 1: going from wakefulness to sleep. The EEG shows alpha waves.
2) stage 2:  light sleep. The EEG will show sleep spindles and K complexes.
3) stage 3: deep sleep. The EEG shows theta and delta waves.
4) stage 4 : deepest sleep. The EEG will show delta waves.
5) REM sleep: We dream during this time. The EEG shows alpha and beta waves.


These stages keep repeating during the night.


sleepwalking never occurs during REM sleep. It always occurs during stage 3 and stage 4 sleep. So sleepwalking occurs
during deepest sleep when the person is not dreaming. So the sleepwalker is not acting out his dreams. He is in deep sleep but
a part of his brain tells him to get up and do something complex! And sometimes the person will not go back to bed unless he has
completed his task! So a person who wants to clean a table will not go back till he has cleaned it all. And repeated attempts to take him
back to bed would be futile because he will keep getting up to finish his task. Also since the first 3rd and 4th stage of sleep occurs
after about 90 minutes of our going to bed so most sleepwalking occurs about 90 minutes after the person goes to bed.


Very little is known about the exact reasons for sleepwalking. During some laboratory experiments it was found that the primitive
sections of the brain showed lots of electrical activity while the higher logical brain such as the neo-cortex was completely devoid
of electrical signals. This shows that the limbic system was in charge of the body’s movements during this time. The logical or
the higher brain(neo-cortex) was sleeping while the body was moving. But remember: the limbic system is also the emotional centre of the
brain. So sleepwalking must have a emotional content.  And that explains why sleepwalking mostly affects people with some emotional
stress. And that is why lots of teenagers show more sleepwalking than adults.


But I don’t think we have explained sleepwalking fully. It is still a mystery of the human brain. Finding answers will need a lot
of research.


Our life is twofold; sleep hath its own world,
A boundary between the things misnamed
Death and existence: sleep hath its own world,
And a wide realm of wild reality,
And dreams in their development have breath,
And tears, and tortures, and the touch of joy;
They leave a weight upon our waking thoughts,
They take a weight from off our waking toils,
They do divide our being; they become
A portion of ourselves as of our time,
And look like heralds of eternity;
They pass like spirits of the past,–they speak
Like sibyls of the future; they have power,–
The tyranny of pleasure and of pain;
They make us what we were not,–what they will,
And shake us with the vision that’s gone by.
( Lord Byron)





Go, wondrous creature! mount where Science guides:
Go, measure earth, weigh air, and state the tides:
Instruct the planets in what orbs to run,
Correct old time and regulate the Sun;