The purpose of this study was to examine the mother's inhibiting or accelerating attitude toward the child when performing in a potentially dangerous situation. It was hypothesized that the mother's attitude might be decided by her cognition of her child's ability to behave with safety. Mothers and teachers of 3-, 4-, and 5-year-old children (n=512) were asked on the children's abilities and behavior characteristics being necessary to handle danger and behave with safety. The results were as follows. (1) The skills to perform in safety increase with age. (2) The degree of mother's prohibiting attitude toward her child does not change with increasing age. (3) The factors that determine the mother's attitude interact with the child's developing aspects of various abilities needed to behave with safety. Based on these results, we constructed a model that presented the factors influencing the mother's prohibiting or accelerating attitude toward the child (FIG.1). Further, a new perspective for concept of a developmental task may be presented here. The developmental task is not to be associated with beh-Rather, each child has his own developmental task avioral norms when he attempts to decrease the discrepancy between the meta-cognition of his abilities and the actual performance. It is suggested that the dynamism of mother-child interaction should be understood on this new concept of developmental task.