The purpose of this study was to explore the effects of negative emotionality and maternal parenting behaviors on young children''s adaptation to child care centers and kindergartens mediated by their effortful control. Specifically, this study focused on effortful control that is predicted to have significant effects on the adaptation to child care centers and kindergartens in multi-dimensional aspects through mothers, teachers and the researcher at home, child care centers and kindergartens, and assignment implementation settings.
The subjects of this study were 364 young children (192 boys and 172 girls) aged 4-5 and enrolled in child care centers or kindergartens located in Daejeon and Chungbuk Province, their mothers and 40 teachers. To measure the level of adaptation to child care centers and kindergartens, this study asked teachers to assess young children with an adapted form of the Preschool Adjustment Questionnaire (PAQ) developed by Jewsuwan, Luster & Kostelnik (1993) and adapted by the researcher for this study. For parenting behaviors, the study had mothers assess their parenting behaviors with IOWA Parent Behavior Inventory-Mother Form (IPBI) developed by Crase, Clark & Pease (1978) and validated by Hong (1995) into ‘Maternal Parenting Behaviors’ which was then modified and complemented by the researcher for this study. For negative emotionality, the study asked mothers to assess their children with an modified form of Rothbart’s (1996) Child Behavior Questionnaire (CBQ) adapted by Kwon (2003) and adapted and modified by the researcher of this study. For young children’s effortful control, the study asked mothers and teachers to assess their children with 27 questions of sub-dimensions of effortful control in the Child Behavior Questionnaire (CBQ) developed by Rothbart (1996), and the researcher measured young children’s effortful control through assignments of the Red-Green Sign. In order to investigate the general trends of measured variables, analysis of descriptive statistics were conducted by using SPSS 21.0 and AMOS 22.0 depending on research questions. In order to investigate the differences in young children’s adaptation to child care centers and kindergartens, their effortful control and negative emotionality and maternal parenting behavior based on general background, t-test, ANOVA, Scheffe post-hoc test and regression analysis were conducted. Furthermore, Pearson’s product-moment correlation coefficient was calculated to examine correlation among sub-factors, Structural Equation Modeling (SEM) to investigate structural relationship among variables and the bootstrap test was used to examine indirect effects.

The Major results of this study were as follows;
First, young children’s negative emotionality had statistically significant effects only on young children’s effortful control measured through their assignments and the higher their negative emotionality such as sadness, discomfort, anger, frustration and fear, the lower the level of effortful control.
Second, maternal parenting behaviors had effects on young children’s effortful control assessed by their mothers and that measured through their assignments. The more of the positive parenting behaviors such as active parental involvement, limit setting, responsiveness, reasoning guidance and intimacy, the higher the level of young children’s effortful control.
Third, young children’s effortful control measured on a given series of tasks and evaluated by teachers had effects on young children’s adaptation to child care centers and kindergartens. That is, the higher young children’s level of effortful control, the more they are likely to have a positive relationship with their peers and teachers, enjoy their lives pleasantly and comfortably, be confident with clear opinions and to understand and follow daily routines well in the child care centers and kindergartens.
Fourth, young children’s negative emotionality and maternal parenting behaviors had effects on young children’s adaptation to child care centers and kindergartens through their effortful control measured by their assignments. That is, effortful control measured by young children’s assignments played a mediating role in this process.
Finally, unlike the results of preceding studies, young children’s negative emotionality and maternal parenting behaviors did not have a direct effect on their adaptation to child care centers and kindergartens.

In conclusion, this study verified that effortful control is affected, and can be developed and improved, by the experience in the environment provided by their mothers even though it is also affected by inherent factors such as temperament. In addition, while most preceding studies in Korea on young children’s effortful control have found out that it is a variable which can predict psychological and social adaption, this study verified that young children’s effortful control is a variable which also has effects on young children’s adaptation to child care centers and kindergartens. This study also confirmed that young children’s effortful control plays a mediating role not only in the process in which negative emotionality has effects on their adaptation to child care centers and kindergartens but also in the process in which parenting behaviors have effects on the adaptation to child care centers and kindergartens. Further, this study has a significant meaning in that it elucidated that young children’s effortful control can manifest itself differently depending on contexts and circumstances.