Middle childhood is both a stage and a pathway to future development. The metaphor of transition (i.e., the pathway) involves looking at markers (i.e., milestones) along the way in order to measure developmental progress. Developmental milestones in middle childhood can be classified into one of four broad domains—physical, cognitive, affective, or social development.

  1. Physical Development.

    In middle childhood, this domain includes biological and neurophysiological development, the refinement of perceptual and motor skills, and physical health, including nutrition and exercise. School-age children undergo rapid spurts in height and weight as well as improvement in athletic abilities. They begin the onset of puberty at varied ages, with 11 years the average age for girls and 13 years for boys, marked first by hormonal changes, followed by observable changes in physical appearance and behavior.

  2. Cognitive Development.

    This domain includes intellectual and language development, reasoning abilities, and memory capacities. The middle years of childhood are characterized by a gradual increase in logical reasoning using concrete examples, increased awareness of memory and learning strategies, and the achievement and consolidation of important academic skills, such as reading, writing, and computing.

  3. Affective Development.

    This domain includes personality, emotional development, motivation, and self-esteem. School-age children acquire personal competencies through participation in academic, athletic, or artistic activities; emotional attachments to family members and others; and a deepening sense of who they are and what they can achieve through serious effort and commitment.

  4. Social Development.

    This domain includes social skills and interpersonal understanding, moral and ethical development, and maintaining close relationships. Youth develop reciprocal understandings of others through family and peer interactions, deepening same-sex friendships, and seeking fairness in their family, school, and peer groups.

Individual children, however, are whole persons, living in the real world and developing as a totality rather than in separate functional domains of development (physical, cognitive, affective, social). Although a great deal of our knowledge about middle childhood comes from studies conducted on specific areas of development, our study of middle childhood takes a holistic approach to human development (Cairns, 2000; Magnusson, 1995, 2000). From a holistic point of view, biological, psychological, and social factors operate together to produce growth and change through reciprocal interaction with the environment, a process that starts at conception and goes on throughout the life span (Magnusson, 1995; Magnusson & Stattin, 2006).