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 4 years solving a tool-using problem to get a food reward. This problem incorporates a skill that is quite common for chimpanzees raised with their biological families. Climbing a pole and leaping free is a common activity for chimps. The object used for a pole is a four-foot-long 2-by-4. A lure was suspended from a tree at a height that was unreachable to Viki without some assistance. The “pole” was the only tool provided to her.