In the 1980s, I was interested in studying the development of perspective-taking in young children. Piaget's "three mountains task" had demonstrated that children find it difficult to understand how something looks to a person who is in a different position from themselves. In fact, younger children exhibit a strong tendency to choose their own view when asked to indicate how an object looks to someone in another position, a tendency that Piaget called "egocentrism." I thought there are three dimensions of egocentrism (up and down, front and back, and left and right), and that children's difficulty in understanding different perspectives might be because they do not receive feedback about other people's perspectives. To test this hypothesis, I conducted a series of experiments with kindergarteners.
Figure 1. Experimental Situation
A:Child,B:Experimenter,C:Sample Photos,D:Place to put toy animal(s),E:Three toy animals,F:Still camera or video camera
The task in the first experiment was to face a camera set up across from them and then to arrange one to three toy animals in a way that would produce a photograph like the sample (Figure 1). Forty-three percent of the four-year-olds exhibited front and back egocentrism by placing the toy animals' backs to the camera. That tendency had mostly disappeared among the five-year-olds and six-year-olds, but it became clear that hardly any of the four- to six-year-olds could position two or three toy animals in the correct left-to-right order. In a second experiment, I used a video camera instead of a still camera and provided video feedback, showing an image of the toy animals as viewed from the opposite side on a color CRT monitor. In the control group, which was shown only the CRT monitor, the children were able to correct their front-back egocentrism on their own but were not informed of their errors. Even in the experimental group, which received instruction and practice in correcting left-right egocentrism, the effect on their post-test results was clearly small (Figure 2).
Figure 2. Mean number correct in each condition
Until the age of about seven, most children facing a teacher who says, "Let's raise our right hands" while raising his or her own right hand will raise their left hands.
Incidentally, research into perspective-taking abilities has traditionally focused on investigating how children understand other people's viewpoints, but I have noticed a serious limitation in the paradigm commonly used to study this. In the case of the "three mountains task," even if children can't directly guess the viewpoint of a person in another position, they can solve the problem by conducting a mental simulation in which they imagine that they have gone to the other person's position, or by a type of mental rotation, in which they imagine that the object has been placed on a lazy Susan and rotated to the correct position. The lack of methodological distinctions in the perspective-taking paradigm was a major problem. As I was worrying about how to think about this problem, I encountered research into "theory of mind." In particular, I spent ten months as a visiting scholar in the Department of Experimental Psychology at the University of Oxford from 1994 to 1995, where I had the opportunity to come into contact with the front lines of British research into cognitive development. After returning to Japan, I began studying "theory of mind," but at that time, hardly anyone else in the country was doing so. Without intending to, I have had to carry out the role of "missionary" in the field of "theory of mind" in Japan.
The most famous experiment in "theory of mind" is the false belief task (the so-called "Sally and Anne task") of Josef Perner and his colleagues. "Sally puts a doll in a basket. While Sally is away, Anne takes the doll out of the basket and puts it into a box nearby. Sally then returns and the child is asked where Sally will look for her doll." In general, three-year-olds can't pass this task, but they become able to do so between the ages of four and six. It has also been demonstrated that even high-functioning autistic children can't pass this task. It is odd that most young children are easily deceived by this task, which is no problem at all for adults. I have been observing the daily lives of children at a Kyoto kindergarten once a week for three years, as well as conducting developmental research, including the false belief task. As a result, I have obtained longitudinal data on "theory of mind" (Figure 3).
Figure 3. Results of a longitudinal study of "theory of mind"
The data presented in this figure began with 15 children, with 4 more children transferring in at the ages of four and five, for a total of 19 children at the end. Only one child regressed from being able to pass the task to failing it, but he was a boy who became extremely nervous and made mistakes in the testing situation at age five and six. The fact that I was conducting experiments on children with whom I was in contact on a daily basis made me feel that I could interpret the results more broadly.