A secondary circular reaction is a concept from Jean Piaget's theory of cognitive development, specifically within the sensorimotor stage, which occurs approximately between the ages of 4 to 8 months. In this stage, infants begin to engage in behaviors that are not just focused on their own bodies (as seen in primary circular reactions) but rather involve the interaction with external objects and their effects on the environment.
In secondary circular reactions, infants will intentionally repeat actions that produce effects in the environment, such as shaking a rattle to make a sound, or moving a toy to see it move in response. This behavior demonstrates an early form of problem-solving and an understanding of cause and effect, as infants learn that their actions can bring about reactions in the world around them. These reactions are considered "secondary" because they involve interaction with the environment, as opposed to primary circular reactions, which are focused on the infant's own body and actions.