Viki’s ability to imitate was first noticed in her play at an early age. As her skills developed, her human “parents” began to develop exercises specifically geared to gauge her imitation abilities and what effect they had on her learning. They implemented an imitative training program at the age of 17 months.

The program included problem-solving tasks, many of which were also presented to human children the same age as Viki and then to lab-raised chimpanzees. The children had much the same educational background as Viki. The results of the children, the lab-raised chimps, and Viki were then compared to determine Viki’s progress in relation to both human children and chimps of the same age.

The clip below is of the “stick-and-string” problem. A piece of fruit was placed into a box with a transparent door on the front. The door could not be opened by hand. A string was placed at the end of a board, attached to the back of the box. The door would fall open at a stern tap of the string. The subjects were then given a stick long enough to reach the string, and the experimenter demonstrated the procedure to open the door. The children needed one to four demonstrations in order to solve the problem. After six demonstrations, the lab-raised chimp made no progress. Viki only needed one demonstration, and then even came up with a solution of her own.