Theory of mind refers to the fact that the awareness states of each individual differs from one another. Means, what a person knows may or may not be known by the other person.
For example, if a person goes to a restaurant, the waiter do not know what that person wants but knows about the food items readily available; and the person knows what he/she want to eat but may not know whether it is readily available or not. Means the awareness states of waiter and customer are different in this case.
Thus, the blank can be filled with theory of mind.