The object concept is the knowledge that objects are permanent, independent entities that exist in space and time even when one cannot perceive or act on them. Humans would be almost unable to function without this knowledge. Although children clearly acquire the object concept early in development, researchers disagree about exactly when and how they acquire it.

Piaget's Theory

The Swiss researcher Jean Piaget proposed the earliest comprehensive account of object concept development in the 1930s. Piaget believed that children gradually construct the concept over the first two years of life in a predictable and universal series of six stages. From birth to three or four months (Stages 1 and 2), infants do not truly perceive objects; they merely recognize stimulation associated with their own subjective experience, such as the reaction of pleasure connected with the sight of a caregiver or an attractive toy...