A child watches a mother move some chocolate while "Maxi" isn't watching. A psychologist asks, "Where will Maxi look for the chocolate?" What concept is the psychologist testing?

The answer is theory of mind.

Explanation:

Theory of mind is a study concerned with the ability to imagine reality through the perspective of a different person. In the example, if the child answers that Maxi will look for the chocolate in the last place he (Maxi) saw it, he's likely developed theory of mind. This means he's able to understand Maxi didn't see the spot where his mother hid it, and thus he has no reason to look for it there.

In daily life, theory of mind is important to understand how other people feel and experience the world.