Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
Date (from‐to) : 2015/04 -2019/03
Author : Kato-Shimizu Mayuko
This study examined whether 4-to5-year-olds showed a tendency to select the inhibited cooperative behavior based on partner’s joint intention. We decided to target 69 4-to5-year-old children as our participants. The results revealed that few children select the inhibited cooperative behavior based on partner’s joint intention, even if the partner clearly showed the intention to do it by oneself. Analyzing the reasons for selections, the children who selected “wait-and-see” cited “actions and mental state of others” as the reason or did not answer. Regarding the relationship between inhibited cooperative behavior and social skills, understanding of other’s mental state influenced the selection of inhibited cooperative behavior based on partner’s joint intention. From these results, the tendency to select the inhibited cooperative behavior gradually developed from about 4-to5-year-olds, and the possibility that theory-of-mind might influence the development was considered.
Menarche is viewed as an important milestone in female development at puberty and develop to sexual maturity is a strategy in life history.The data by random sampling from the complete school-list of Japan was consisted of 41,838 schoolgirls (9-15 years old). The mean age at menarche of Japanese schoolgirls in 2015 was 12years and 1.7months by status quo data. The menarcheal age of those who eat breakfast infrequently and sleep shorter lengths of time tended to decrease. Our questionnaires included psychological questions about gender acceptance and desired future job. The peak age of wanting to be a preschool teacher was 12years, which was the same as the peak of experiencing menarche. This phenomenon shows strong interest in infants among girls at puberty. However, the numbers of girls experiencing menarche was less than the number of non-experiencing among the girls choosing preschool teacher. And early matured females had negative gender acceptance.
Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
Date (from‐to) : 2013/04 -2015/03
Author : SHIMIZU MAYUKO
To maintain cooperation with a large population, selective prosocial behavior based on second-order information (information about the characteristics of a previous partner of the partner) is essential. In the present study, we examined how selective prosocial behavior based on second-order information develops during early infancy. Our experiments were carried out with infants of 8-month-olds and 16-month-olds. While 16-month-olds showed prosocial behavior based on second-order information, 8-month-olds didn’t show such behavior. It is suggested that infants’ prosocial behavior become based on more complex information about the context in which partner's behavior is performed after the first year of life.
The material collected in February2011 consisted of a random sampling of45,830schoolgirls (9-15 years old). The mean age at menarche of Japanese schoolgirls was found to be 12.189 years (12 years and 2.3 months.) In comparison with the mean age of 2008, the mean age had not significantly changed. The mean menarcheal age in Japan was thought to be decreasing since the 1990s. The trend towards early maturation in Japan had obviously leveled off.The age of menarche serves, as well as an evolutionary index, as a reliable instrument with which the health practice and socio-economical difference of each region may be measured.
The material collected in February2008 consisted of a random sampling of 41,798 schoolgirls (9-15 years old). The mean age at menarche of Japanese schoolgirls was found to be 12.189 years (12 years and 2.3 months.) In comparison with the mean age of 2005, the mean age had not significantly changed. The mean menarcheal age in Japan was thought to be decreasing since the 1990s. The trend towards early maturation in Japan had obviously leveled off. The age of menarche serves as a reliable instrument with which the health practice and socio-economical difference of each region may be measured.