Dr. Harlow's Rhesus Monkeys

This video with the monkeys is critical to motor development.  It shows how the monkeys like human are drawn to the soft mother rather than the wire monkey.  The only reason the baby monkey went to the wire monkey was for nourishment.  As soon as the monkeys finished eating they would return to the soft mother.  This had a devastating affect on the monkeys socially, they were not able to interact later in life.  They were scared and confused.  This is just one more reason to love your children.