Marshmallows, sardines, and prunes dipped in “sardine juice” helped scientists learn more about problem-solving in raccoons as they forage for meals. These so-called “trash pandas” appear to be motivated to solve problems by more than access to snacks, the study revealed. The scientists started by figuring out which of the three tasty treats each of 15 raccoons liked best, placing each treat on a separate paper plate and noting which morsel individuals chose first. Then, the team cached each raccoon’s preferred treat in its own personalized puzzle box and watched the raccoons’ behavior.

Even after the racoons solved one puzzle to get their favorite treat, they proceeded to keep solving the other puzzles on the box without a reward. Turns out, both knowledge and marshmallows are delicious!

You and I go out to eat at a conveyer-belt sushi restaurant. It serves four types of sushi: ahi roll, Boston roll, caterpillar roll and dragon roll. We each have access to our own conveyer belt that the chef loads continuously at random. Every plate has one piece of sushi on it, and each costs the same amount. We agree that I will eat every piece of sushi on my belt until I get two ahi rolls in a row, while you will eat every piece of sushi on your belt until you get an ahi roll followed immediately by a Boston roll. Whose meal do you expect to cost more?