Eleven-month-old Luis watches as his mother comes in and out of his bedroom while she is putting away laundry. Luis does not get upset when his mother leaves the room since he seems to know that his mother is still in the house, even if he cannot see her. Luis is demonstrating .

Luis is demonstrating Object Permanence .

Explanation:

Object Permanence is a term that describes how a child understands that an object is existing even though the child can no longer see or hear it.  

Usually, infants at a certain age do get upset and cry whenever an object has been hidden from them because they are yet to attain the understanding that an object continues to exist even when they can no longer see or hear from it.

On his part, eleven-month-old Luis has reached a stage where he understands that his mom is somewhere close to him even though he can't see or hear from her.