Discovering “Empathetic” Amongst Rats

Public Relations Office        May 30, 2017

Nobuya SATO, Professor, School of Humanities, Department of Integrated Psychological Sciences

Nobuya SATO, Professor, School of Humanities, Department of Integrated Psychological Sciences

In 2000, Sato completed the doctoral program at the Hiroshima University Graduate School of Biosphere Science. He spent time as a researcher at the Kyoto University Primate Research Institute and was awarded a Research Fellowship for Young Scientists and a Postdoctoral Fellowship for Research Abroad from the Japan Society for the Promotion of Science before joining the faculty of the Department of Integrated Psychological Sciences in Kwansei Gakuin University’s School of Humanities as an Associate Professor in 2009. He became a full professor in 2014. Sato’s areas of specialization are cognitive neuroscience, neurophysiology and behavioral neuroscience.

A research group led by Professor Nobuya Sato in the School of Humanities’ Department of Integrated Psychological Sciences has experimentally shown that rats are empathetic towards, and will offer help to, other rats who are in trouble. Here, we introduce this research which was published in the comparative cognitive science journal Animal Cognition.


In the experiment, two see-through rooms (each 20 centimeters square) attached by a door are prepared, and one of the rooms is filled with five centimeters of water. Two rats which have been housed together for two weeks are put into the rooms: one into the water-filled room and one into the dry room. In more than 90% of cases, the rat in the dry room would open the door to help the rat in the water-filled room.

When both rooms were dry, no rat would open the door for the other. Furthermore, rats who had previously been subjected to the waterfilled room were quicker to open the door for another rat when put into the dry room.

Also, when rats in the dry room were presented with a choice between the door to the rat in the water-filled food, the rats in the dry room tended to choose the door to the water-filled room over the room with food.

These experiments show that rats will prioritize other rats with whom they feel a connection over obtaining food, thus suggesting that they empathize with fellow rats who are stuck in unfortunate conditions.

In psychology, voluntarily providing a benefit to another without any expectation of reward is known as “prosocial behavior.” Prosocial behavior is believed to be rooted in the experience of having empathy for others. This behavior was thought to be unique to primates; however, beginning with a paper that a group room and a door to a room containing of University of Chicago published in the journal Science in 2011, researchers have come to realize that rats also express prosocial behavior.

Change in latency for the door-opning by the helper rats

Professor Sato and his students (of those days) continued the line of study based on the prior research conducted in 2011. When planning their research, Professor Sato’s group wondered if the rats who were the recipients of aid in the prior research were truly in unpleasant circumstances. They decided to create a situation which would be genuinely unpleasant for a rat, and thus they chose immersion in water.

On May 12, 2015, they published a paper summarizing the results of their research. The findings were covered by major media in Japan as well as around 60 overseas media outlets, including the Washington Post newspaper in the US, the CBC public broadcasting company in Canada and the BBC public broadcasting company in the UK.
Regarding the research, Professor Sato said, “Empathy is extremely important to humans’ ability to live in social groups. Rats, just like humans,

are mammals and have similarly constructed brains. I believe this research will help us better understand the neural mechanism mechanisms found in humans and how they have evolved.”

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