What is meant by a "theory of mind" as it applies to autism, and how can it be illustrated?

Answer:

The theory is that people with autism fail to appreciate that other people have a point of reference that differs from their own. In the "Sally-Ann task," the child is shown two dolls, Sally who has a basket, and Ann who has a box. While Sally is gone, Ann takes a marble out of Sally's basket and puts it in her box. The child is then asked where will Sally look for the marble when she returns. Sally, of course, should look for the marble in her basket, because that is where it was when she left, and she did not see Ann hide it in the box. However, children with autism, lacking a theory of mind, fail to appreciate Sally's perspective and say Sally should look in the box because that is what they saw.