Let me explain about what today's brain science says about the body by taking up examples of popular characters. Mobile suits of Gundam and Kamen Rider (Masked Rider) as extensions of the body are getting particularly realistic and life-size in recent years. You know as basic knowledge that there is homunculus (midget) inside the brain. In this homunculus, parts of the cerebral cortex which control parts of the body important for movement are exaggerated and drawn larger than the actual body size. This represents that cognition of our bodies is proportionate to the area of the part of this cerebral cortex. For example, parts of the cerebral cortex that controls the eyes, ears and finger tips, which are required to have the capacity for extraordinary precision, are drawn large. This body image is not fixed. In fact, body image changes most dramatically amongst all images. There was a classical experiment in which the brain perceived that the body was extended by the use of tools. It was conducted with a monkey bringing food towards itself with a rake. The rake must be used actively, and not just held physically. People practice golf swings and Ichiro swings the bat to get the feeling. If these are interpreted based on experimental data, it is interpreted that the body image is being extended. This is a bit complicated but there is the famous case of Horatio Nelson's phantom limb (Battle of Trafalgar). It is well known that Admiral Nelson did not lose the sensation of pain even after he lost his right arm. In other words, it is a very troublesome condition where even when a hand is physically lost, the feeling of the hand and pain remains as hallucinatory pain in the brain. It is a brain disorder in which the hand that no longer exists hurts excruciatingly and is painful both mentally and physically. Nowadays, operations, or rather psychological treatments, have been developed to remove phantom limbs. Body images are constantly recreated through coordination between output of movement and sensory feelings. The treatment is conducted by using this feedback mechanism. Even though there is no right hand, there is the left hand. The left hand is put inside a mirror box and an image is created in the brain as if the right hand exists by observing different kinds of movements of the hand with the eyes. When the left hand is moved a visual image is created as if the right hand reflected in the mirror moves, but in fact an order to move the right hand has not been given so the brain realizes this contradiction. By using this contradiction, the part of the brain which hallucinated the existence of the right hand is erased. This is an experiment of the operation to remove a phantom limb, and it shows how very dramatic changes occur in body images.

 I will relate this to costume play later on, but I think that first person cognition of character is related to change in body image. Nothing changes so dramatically in such a short time inside the human brain as body image. That is why there is such thing as identification of the body feelings with riding a vehicle etc. This is so because, in the space of vision, there is no extreme change such as the right side suddenly becoming the left, but since the body moves all the time, the brain expects this and prepares plasticity. It rewrites the map one after another in accordance with the movement. Therefore, as far as character recognition is concerned, what is important from the point of view of the brain is the issue of corporeality.

 In fact, the body and communication are very deeply related. Let me explain giving an example from the film 'Tokyo Monogatari' by Ozu Yasujiro. The scene is where the old woman dies when the elderly couple returns to Onomichi. The son who is a doctor, the daughter, the husband, and the son's wife watch over the old woman in her sick bed. This film is a great classic which became number one out of the best 100 films in the history of world cinema in a recent survey by a British film critic, and I think it is a work we Japanese should be proud of. In this scene, there are all sorts of things that can be read from the expression on the son's face. For example, sadness that his mother is going to die, but on the other hand, there is the sense of duty from his professional consciousness as a doctor that he must remain calm till the end. The expression of the old man Shukichi who reads his son's feelings is amazing. We can see such complex and subtle movements of the mind. Such ability by humans to read the mind of another is an amazing ability. Today, robots walk with two legs but that in itself is not particularly amazing. In other words, it comes no where near the human intellectual ability to read another person's mind. For example, the daughter who is a hairdresser and appears cold at first sight, suddenly asks out of context, 'Have you brought mourning clothes?' Human beings do such unexpected things. I said that emotions evolved as an adaptation to uncertainty, but in fact for humans the most important uncertainty is presented by the minds of others. It is uncertain whether a girl will like you or not, and generally speaking, nothing is as uncertain as the mind of another person. It is amazing to have the ability to read this. I think many of you know about it. It is called the theory of mind and is a human ability to read the state of another's mind. Theory of mind is one of the most important topics in brain science and cognitive science over the last thirty years. It is a theory through which one can read the mind of human beings, who could do anything, to some extent. One cannot read another's mind completely but can read it to some extent.

 Mirror neuron is the most important discovery in the past ten years in studies of theory of mind. Some people say that it is a great discovery in brain science that can be said to equal the discovery of the double helix structure of DNA. Mirror neuron is a nerve cell located in the frontal lobe region called premotor area, and is a nerve cell which acts in the same way both when one is doing something and when watching another doing the same thing, as if seeing a mirror. A brain scientist started eating gelato when he was investigating a monkey. By accident, he discovered that each time he brought gelato to his mouth, the cerebral cortex region of the monkey who was watching this was activated. When he conducted an investigation, it was found that this was originally the nerve cell which was active when the monkey brought food to its mouth by itself. In the history of discovery in brain science, discoveries which are made with the expectation that such cells exist are usually not exciting. Great discoveries are made accidentally completely out of context; in this case, the Italian researcher's random act of eating gelato in front of a monkey during the research fortunately led to the discovery. Mirror neurons really surprised people because it is very deeply related to the theory of mind in which one reads the mind of another. It is said that one can replace the actions or facial expressions of others on to one's own behavior and simulate them due to the functioning of mirror neurons.

 In the process of development of humans, the realization that one has a mind and that a mind exists in the other, that is to say, the theory of mind, emerge simultaneously at around the age of four. There is a test to determine self consciousness called 'the mirror test' devised by the American ethologist Gallup. An animal is placed in front of a mirror and a mark is put on a part of the animal's face. Tests are conducted on the assumption that if the animal recognizes that the image in the mirror is itself, it will try to take off the mark. So far, the only animals that pass this test are humans, orangutans, chimpanzees and dolphins. Gorillas fail. It has not been proved that these four species have self consciousness, but the important point of this mirror test lies in the fact that the recognition of one's own mind and recognition of another's mind emerge almost simultaneously by using a common mechanism of the brain. I gave an example above of Bowlby's theory of 'safe haven' as a way of thinking about human development. Relationship with the other, in other words, the relationship of being watched, has a very important significance and influence. My friend Philippe Rochat from Emory University in America often talks about the following case. A girl stands at the very front of the queue of a diving board in a swimming pool. She is going jump now but does not do so easily. She does not jump because she wants her mother who is at the poolside to see the moment she jumps and the mother is not looking. No matter how many children are waiting behind her, she will not jump until her mother looks at her. For this girl, an action which is not seen by a person dear to her is the same as not happening at all. That is to say, from the first stages of a child's development, the meaning of action is socially determined. For example, a child probably only cries when the guardian is present. It is often the case that a child gets hurt somewhere, comes home, and starts crying just as he/she sees the mother's face. It is said that the child feels relieved by seeing the mother's face and cries, but in fact the child cries because the act of 'crying' has social meaning, and the human brain is developed on the presupposition that it is seen by others.