When humans cooperate on a task, they will think about how much effort is required in their own and their partner’s actions. For example, if you are baking a cake with someone, you might think about letting them mix the bowl while you take care of other things, such as reading the recipe and setting the temperature of the oven. You may take on this extra effort, so your friend doesn’t have to, or even to get the baking done as quickly as possible. Our question is: do chimpanzees consider action effort and efficiency in tasks, and does this impact their decision to work alone or with a partner?

To test this, we have a vertical maze puzzle box. The chimpanzees must use their fingers to move a delicious juicy ice cube along platform levels, so it falls through holes to the bottom level where it can be retrieved. Depending on their choice, the puzzle boxes have a long route or a short route. Do they plan ahead and choose the short route to get their reward more quickly and use less effort? Also, if the experimenter takes on some of the effort of moving the ice cube, will chimpanzees prefer to cooperate or still work on their own? These are questions that we can try to answer with this puzzle box. If the chimpanzees show a preference for low effort and high efficiency in this task, we can learn more about their decision making, action planning, and cooperative capabilities. Humans may not be the only species who consider a task’s effort and efficiency!