The tertiary circular reactions definition in Piagetian theory is an infant’s action that creatively modifies former schemes to adapt to the requirements of new situations. Such reactions occur close to the end of the sensorimotor stage at about the beginning of the 2nd year.


The tertiary circular reactions vary from earlier behaviors of the child and indicate that it can develop new schemes to achieve a desired goal for the first time throughout the developmental stage. They are also called the discovery of new means through active experimentation.

Piaget’s theory of cognitive development entails four stages, where the sensorimotor stage is the first one that covers the period from birth to nearly two years. Furthermore, it is a period of rapid cognitive growth. Such a period implies that infants promote their understanding of the world through trial and error through their senses and actions. Therefore, actions become progressively attuned to the world as the child is engaged in the processes of assimilation and accommodation.

With that said, the sensorimotor stage of development can be divided into six additional sub-stages, such as simple reflexes, primary circular reactions, secondary circular reactions, coordination of reactions, tertiary circular reactions, and early symbolic thought. The stage of tertiary circular reactions is the fifth step of development that differs from the secondary circular reactions.

The tertiary circular reactions are characterized by being intentional adjustments to particular situations. The tertiary circular reactions examples include the infant who previously explored an object by taking it apart now tries to put it back together. For instance, an infant may stack the bricks of the wooden truck back again or put back the nesting cups.