Describe the sensorimotor stage in the development of infants (0-2 years old).

In the very early stages of life, objects are literally "out of sight, out of mind." Infants don't initially represent objects in memory. Later, they acquire object permanence, the understanding that objects exists even when out of sight. Young children will learn many concrete concepts (e.g. Mom, Dad, cat) and they form a conceptual foundation for later learning (Rakinson, 2010). Children at this stage also develop the ability to imitate, which allows them to learn by observing others.