Rats Enjoy Playing Hide-and-Seek

A new study published in the journal Science (Reinhold et al., 2019) reported that laboratory rats learned to play hide-and-seek with researchers at Humboldt University of Berlin, in a novel approach to studying the neural underpinnings of decision-making and motivation. Normally, scientists studying these aspects of neurobiology train confined animals to perform tasks (e.g., lever pressing) in exchange for liquid or food rewards. This new “game” approach, which allows rats to retain agency and express “rich, unrestricted behavior,” is also fun—rats were eager to play and made “joy jumps” during the game. In a large room with boxes and panels that offered cover, rats were trained to alternate between hiding until they were found by the researchers, and seeking researchers who were hiding. Finding and being found were rewarded with playful tickling. Rats quickly grasped the game and played strategically: When hiding (versus seeking), they made fewer vocalizations and chose opaque cover. This story seems like a win for animals and science, too.