Child development is a sub area of the discipline of developmental psychology. Child development identifies and describes changes in the child cognitive, emotional, motor, and social capacities and behaviours from the moment of conception through the period of adolescence. The field attempts to uncover the processes that underlie these changes to help explain how and why they occur. One of the earliest and most significant events in canadian developmental psychology was the appointment of james mark baldwin to university of toronto in 1889. Baldwin used his own daughter as a subject, he examined and published papers on topics such as handedness, suggestion and will in infancy, and imitation. Vital aspects of development are biological, cognitive, linguistic, emotional, and social. Origins of behaviour: biological vs. environmental influences. Arnold gesell believed that the course of development was largely predetermined by biological factors. In his research gesell focused on maturation, or the natural unfolding of development over the course of growth.