Q: How important are the early years to successful life-long learning?
Sakai: It depends, because there may not be one single mechanism for lifelong learning. I think that language acquisition is unique compared with other learning skills. Although we can learn any language after puberty, but its performance is quite different from one's own native language that is special throughout life. There are issues regarding learning English earlier for non-native English children. For example in Japan, the Ministry is trying to promote English conversation lessons even in elementary schools, on the assumption that "earlier is better". However, learning conversation like "How are you?" - "Fine, thank you. And you?" is just a phrase association. That skill may be based on general associative mechanisms, but it could be radically different from language acquisition, because there are no syntactic structures in such a kind of learning. For successful life-long learning, I think that the use of native language for logical thinking is far more important than hastily learning other languages during the early years.

Q: To what extent do age-related factors determine the successful learning of specific skills, attitudes, and knowledge?
Sakai: There is a classic study by Johnson and Newport, which shows that at certain times in life there may be an important condition - called a critical period - for determining second language performance. The subjects, Chinese and Korean born residences of the United States, were grouped according to their age when they moved to the US. Those who came to the States between three to seven years old had language performance more like a native than others. But after that, individual differences become very significant, and mean scores go down as the age of arrival increases. One might argue that the human brain function sets earlier in life and that ability to adapt to a new environment - a new language environment - is somehow lost. However, this process may depend more on the people's motivation and capability later in life, even if age-related factors appear to play a critical role early on.

There is another classic proposal by Lenneberg about first language acquisition. The clinical observation suggests that people with some lesions in the left brain recover quickly from language disorders before puberty, but after that, adults tend to experience more difficulty in recovering. This means that until puberty the brain has more flexible plasticity to cope with acquired lesions. It also suggests a limited capacity for entire lifelong learning, but we are not sure how far we can exploit our own capabilities.

Q: Is the brain a spontaneous learning machine?
Sakai: I think so, yes. It also depends on what you learn. As for language, I think that Pat Kuhl has shown quite clearly that the brain is an automatic language-learning machine. The infants can quickly pick up various sound parameters of a native language. It is achieved in a very interesting and special manner, because it doesn't require any conscious effort or explicit knowledge. I think this language process represents a unique acquisition mechanism.

Q: Can there be learning without emotion?
Sakai: It is true that emotion, motivation, or social factors can influence the attitude toward new learning. If you are not interested in learning something at all, the learning effect would remain minimal. Emotion and other general environmental factors can affect learning, but it's very difficult to prove it scientifically. Even when genetic and environmental factors are similar, like identical twins, you cannot completely control learner's motivation. Even if you are presented with the same task, the internal conditions of individuals are so different that the learning experience can become different, too.

Q: Do you see any ethical issues emerging from a neuroscientific approach to learning?
Sakai: We have to consider not only human rights but also ethical issues for any experimental approaches for learning or education. For example, suppose that you design an interesting training program that requires a blind control group. Now, let's suppose that the training works. Once the training results are known to the subjects, the trained person may be very happy, but the control remains unstatisfied and wants the benefit from the training. This will create an ethical problem. It would be ideal to provide equal opportunities for both groups, such that the previous control group become the trained group in the next session. We should always keep considering benefits for every valued subjects.