Sensorimotor Stage

In the sensorimotor stage, the infant orients himself or herself to objects in

the world by consistent physical (motor) movements in response to those

sensory stimuli that represent the same object (for example, the sight of a

face, the sound of footsteps, or a voice all represent “mother”). The relationship

between motor responses and reappearing objects becomes progressively

more complex and varied in the normal course of development. First,

reflexes such as sucking become more efficient; then sequences of learned

actions that bring pleasure are repeated (circular reactions). These learned

reactions are directed first toward the infant’s own body (thumb sucking),

then toward objects in the environment (the infant’s stuffed toy).

The baby seems to lack an awareness that objects continue to exist when

they are outside the range of his or her senses. When the familiar toy of an

infant is hidden, he or she does not search for it; it is as if it has disappeared

from reality. As the sensorimotor infant matures, the infant becomes convinced

of the continuing existence of objects that disappear in less obvious

ways for longer intervals of time. By eighteen months of age, most toddlers

have achieved such a conviction of continuing existence, or object permanence.