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?
a) sensorimotor
b) preoperational
c) concrete operations
d) formal operations

ANS: A, Ashani seems to suffer from a lack of object permanence, which is noted during the sensorimotor stage of Piaget's theory.