The Egocentric Encoding In The Children's Spatial Reorientation

The research about the ability of spatial re-orientation is one of the paradigms of the study of the brain spatial representation. Most researches about children's ability of spatial re-orientation aim at investigating whether children use the simple geometric information or use the special landmark to find the objects. As far as we known, there are two kinds of spatial representation. One is the environment-centered representation, including geometric information and landmarks; the other is the self-centered representation, including the spatial relationship between self and objects and the spatial relationship between self and environment. However, the effect of egocentric encoding in the children's spatial reorientation is rarely investigated in the previous researches in children re-orientation researches. In Lourenco's experiment, they change the subjects'viewpoints by manipulating the displacement process and the result of the experiment preliminarily show that children's ability of reorientation in space is not only dependent on the geometric information, but also rely on the relationship between viewpoints and objects. Nevertheless, this experiment does not further investigate the relationship between egocentric encoding and environmental codes in children spatial re-orientation researches and its experiment paradigm increases the difficulties of the task compared with the traditional paradigm in children spatial re-orientation research.In order to investigate the problem mentioned above, we manipulate the changes of the subject's viewpoint in traditional paradigm in children spatial re-orientation research., so that we can further investigate the effect of self-environment encoding in children's spatial re-orientation experiment.In experiment 1, we manipulate changes of the geometric structure faced by children in order to investigate whether children can make use of the changes in self-environment representation to find the hidden objects. The results show when the children face the same geometric structure before and after circular motion, the "geometry (+) body (+)" corner is searched significantly more than the "geometry (+) body (-)" corner by children. When the children face the different geometric structure, the search rates of these two corners are not significant different. According to the theory of geometric model, regardless whether the geometric structure faced by children before and after circular motion maintains same or not, the rectangular geometry information of environment is unchanged, so that the research rates of "geometry (+) body (-)" corner and" geometry (+) body (-) "corner should not be significantly different in these two conditions, but the result is not such the case.The result of the experiment 1 demonstrates that children do not just rely on geometric information in environment, but will make use of self-environment representation, self-object representation and environment-object representation together in spatial re-orientation task. When children opened their eyes after circular motion, they will update these three kinds of representation firstly. If children's self-environment representation maintain same after the circular motion, in another word, children's self position does not change after a circular motion compared with their initial self position, then children will be directly to make use of the self-object representation to search the hidden object. If children's self position has changed after a circular motion compared with their initial position, then children will be not directly to make use of the self-object representation to search the hidden object. They shall firstly relocate their initial position and update the self-environment presentation, then make use of the self-object representation to find the hidden object.In experiment 2, based on the result of experiment 1, we further investigate whether children can make use of more complex geometry information to determine the differences in self-environment representation by letting the children to face the corner. When children face the corner, it is the combination geometric information needed to be used by children to determine the differences in self-environment representation not the direct angle information. The results show when children face the same geometric structure before and after circular motion (0 degree sand 180 degrees), the "geometry (+) body (+)" corner was searched significantly more than the other corners. In such a condition, children consider that the self-environment representation maintain same, so they go directly to search the front corner. When children face the different geometric structure before and after circular motion (90 degrees and 270 degrees), the" geometry (-) body (+)" corner is searched significantly more than the "geometry (+) body (+)" corner and is also significantly more than other two corners. In other words, even the present front corner is no longer the same corner which has the same geometric information compared with the initial faced corner before circular motion, but now the children can only use the complex combination geometric information to determine whether the self-environment representation maintain same or not. The results show that children can not make accurate judgment on the difference in representation, so they directly to search the present front corner based on the present self-object representation. The results of experiment 2 also demonstrate that children do not only use the geometric information to find the hidden object, and such more complex geometric information can not be easily used by children to update self-environment representation.Both the results of two experiments show that children do not only make use of the geometric information to find hidden object in spatial re-orientation task. The fact is that finding the hidden object in spatial re-orientation task is based on comprehensive use of the self-environment representation, the self-object representation and the environment-object representation.