Abstract: This is a longitudinal study. Using a tentative mental scale, theauthors administered the mental tests to 29 children each month frombirth to 36 months. At the same time they recorded and analysed themothers' detailed reports. The purposes of this study are: (1) to collectthe children's normative data in five areas (gross motor, fine motor,language, adaptive behavior and personal-social behavior) in their firstthree years; (2) to study the factors which affected the mentaldevelopment of children under three years of age. The authors also discussed topics such as: patterns of thedevelopmental process, mental activity levels of performing cognitivetasks, influences of personality upon mental development of childrenand the main indicators of mental abilities, etc.

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