[2] Smith's works are groundbreaking and illuminating for the field of perception, action, language, and categorization, showing the unique flexibility found in human behavior.
[21] Smith's research examines developmental processes, and mechanisms of change, in perceptual, motor, cognitive, and language development in infancy and early childhood.
[3] Together with Esther Thelen, Smith proposed a detailed theory of early perceptual, cognitive, and motor development based on dynamic systems.
[22] Dynamic systems theory is a mathematical approach to understanding developmental processes, including evolution and culture, with cumulative incremental changes leading to increases in behavioral complexity over time.
[3] Smith and Thelen emphasized the role of exploration and selection in the self-organization of perceptual-action (sensorimotor) categories, and the cascading interactions between perception, action, and attention over time.
[23] This term refers to children's tendency to extend usage of a newly introduced noun to other exemplars of the category on the basis of the shape of the object, rather than its color, texture, or material.