Ashani is 18 months old. When her mom leaves her at the babysitter's house, Ashani cries initially. After a few moments, she stops crying because her mom is "out of sight and out of mind." According to Piaget, which period of cognitive development would Ashani be in?

Sensorimotor

Explanation:

Jean Piaget developed a theory on cognitive development that starts from when we are born and finish by the time we become teenagers.

According to Piaget babies go through different stages in which they acquire new ways of thinking and structuring the world they are in and they develop their cognition.

The sensorimotor stage is the first of Piaget's stages, it lasts from birth and until age 2 approximately. In this stage, infants gain a basic understanding of the world around them based on their senses and motor abilities.

One of the main accomplishments in this stage is called Object Permanence and it refers to the fact that the kid knows that people and objects keep existing even when they are out of their sight. Kids that have not developed object permanence yet, think that a person disappears when it's out of sight (That's why younger babies have so much fun playing peek-a-boo).

In this example we see that Ashani has developed Object Permanence, because even though she initially cries when her mom leaves, she stops crying because she knows her mom keeps existing in the real world even when Ashani cannot see her. Therefore she is in the sensorimotor stage.