Viki was often rewarded with food when she solved tool-using problems. Even though she had learned to use tools in play and by imitation, the motivation of getting food as a reward was also a valuable tool with which to help her learn new skills at early ages.

Here, Viki is shown at 3 years solving a tool-using problem to get a food reward. In this problem, a lure is suspended, and the “tool” provided to Viki is a ball. She figured out the solution before she was shown. It just took her a few tries to make an accurate throw.