Study Shows Rats Show Regret


That squeaking noise rats make may be an example of rats saying “Rats!” as a new study says that rats show regret. A new study from the University of Minnesota says that the rats tested would show regretful behavior after making bad choices. Rats are the first non-human mammal to demonstrate regret. Like in humans, the regretful behaviors came after the rats made a choice regarding food.

Neuroscience professor David Redish set up an experiment where students would take note of the time rats would take before deciding to move on. The experiment had a circle of tunnels, each with a different food choice. As the rat moved through the circle, a tone would sound at each food station. The tones were all of a different length, and the rat would have to decide whether or not to wait for the tone to end or move onto the next food station. The students figured out which foods rats liked the most, and tailored the test so that they would have to wait the longest for the food they liked. When they passed up a short wait for a long wait, the rats acted regretful

Redish’s study shows that when the rats thought they made a bad choice, they acted out in regretful ways. Regretful behavior in rats is not the same as in humans. Regret in rats equals rushing for food they did not like, as if they regretted having to wait for the food they did. And when rats would pass up a short wait for a longer one, they would gaze back to the short wait station. Brain scans also revealed activity in areas of the rat’s brain that would correspond to regretful activity in human brains.

One of the key problems in the study was differentiating between regret and disappointment. Disappointment is showing a reaction to a bad time, which animals have been known to demonstrate. Regret means that the rat knows it has made a choice and reflected on that choice. Other scientists are looking forward to adding new wrinkles into the experiment, like how addiction affects regret.

The area of the brain affected by regret is the orbitofrontal cortex. The rats show regret over the things that they did not do, not the things they did not get. The orbitofrontal cortex is the same area of the brain active when humans express regret. The showing of regret is an outward expression of the knowledge of making a mistake. Redish and his students recorded the brain activity by hooking electrodes into four rat brains and taking readings through them. The rats brains would react differently for each food choice. That is how the scientists could figure out which choice the rat wanted more and which they regretted taking.

This study, showing that rats show regret, is an important step for animal behaviorists and neuroscientists alike. The brain remains an elusive topic for science, and every step in understanding it is an important one. Of course, the only rats that do not show regret are the ones that follow their dreams of becoming a French chef.

By Bryan Levy

National Geographic
Science Codex

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