Answer to Question 1
Theory of mind refers to the awareness among four-year-old children that other children may have different conceptions of the world than they do and that these conceptions are subject to change as more information is acquired.
Answer to Question 2
Sharing one's perspective on a particular idea with others who have different views leads to adding to, deleting from, or modifying one's original position, thereby allowing one to build a more comprehensive and accurate picture of the world.