Experimental study of the ability to act "in the mind" in early childhood is presented. Studies aimed to establish the state of the function have revealed that 1-2 years old children are capable of recognizing the original in copies differing in the degree of resemblance (mirror reflections, color and black-and-white photographs, incomplete representations), as well as of dealing with the copies in a similar way to how they dealt with the original. The children performed better when given images of people, and worse - when given images of things. Directed development in children of a more complicated form of communication ("business"-like instead of "personal") promotes considerable progress in the ability to behave "in the mind". Communication with adults has proved to be an important factor at the early stages of intelligence development.