The purpose of this paper was to compare previous research with “school caste,” which is the phenomenon of status hierarchy between informal groups among Japanese classrooms, and to discuss the direction and perspective of research on school caste. In the current study, we reviewed studies on sociometric popularity, perceived popularity, and peer crowds as research knowledge on children’s social status in schools. We then reviewed literature reports on school caste and discussed how school caste would be positioned as studies on social status among schools. After indicating the problems of promoting research on school caste, we discussed the future direction of research. Finally, we discussed the implications and directions of future empirical studies on school caste or interpeer group status, based on the aforementioned review.

Many studies show that, when children learn new content words, they can utilize the appropriate types and appropriate amount of linguistic information. However, no existing study has examined what factors influence children to select the appropriate types and appropriate amount of linguistic information. In this study, we reviewed previous research on how children learn content words that are appropriate for their linguistic context. Through our review of the literature, we found three factors—validity, frequency, and redundancy—that influence how children select linguistic information. Based on these three factors, we further introduced studies that highlight the effectiveness of linguistic information on function word learning to understand how children learn function words, and how the factors affect function word learning in children. Existing studies also report that linguistic information is involved in function word learning. The three factors also affected the selection of their linguistic information. However, the extent that validity, frequency, and redundancy affected content words varied. In particular, linguistic information with a high validity is effective for learning content words, but not for learning function words.

This paper investigated the developmental process by which children learn to appropriately judge the authenticity of a facial expression that is deliberately controlled. The results showed that difficulty in judgment varied, depending on the type of facial expression, and that smiles were easy to judge. However, children cannot scan the eyes, which provide a useful cue for smiles. Through reviewing previous studies, the following process was suggested. Children are initially poor at scanning facial expressions and do not know which part of the face they need to look at. Children then generally start to look at the eyes when they are about to recognize an emotion from a facial expression. Furthermore, they compare the situation and the facial expression and notice inconsistencies between them. They thereafter learn that the eyes appear different when a person does not actually feel happy. Finally, future research directions are discussed.