Scientists often use laboratory mice for research purposes. As it turns out, the behaviors of these small rodents can be more complex than assumed. Just because they don't follow a command doesn't mean they don't understand it.

Mice are almost everywhere: in abandoned buildings, at metro stations, and some even keep them as pets. These rodents have also found application in science, as they are used as laboratory animals. Why do researchers choose mice for numerous experiments? They chose them for a simple reason: these little creatures are easily motivated to perform simple tasks in exchange for, for example, a bit of food.

Laboratory mice surprised scientists

However, there are times when mice behave contrary to the expectations of scientists and fail to perform the tasks assigned to them, such as navigating a maze or pressing a specific switch. Until now, researchers believed this was due to the animals' inattention. However, the authors of the latest study published in the journal "Current Biology" suggest that mice can deliberately act on their own.

"Probably, mice have a richer inner life than we think. They are not just stimulus-reacting machines. They may have their own strategies for action," comments Kishore Kuchibhotla from Johns Hopkins University, the study's author.

As part of the study, scientists taught 13 thirsty rodents to turn a wheel in a specific direction indicated by specific sounds. One sound corresponded to turning the wheel to the right, and another to the left. If a mouse responded correctly, it received water. In case of an incorrect reaction, there was no reward.

Intriguing experiment

In thousands of trials, researchers noticed several patterns. Over time, mice got better at it, suggesting they mastered the assigned task. However, even after reaching an expert level, they still made erroneous interactions. Regardless of the sound played, they turned the wheel in one direction.

To better understand this, the study authors stopped rewarding mice for correct answers. Then, the rodents returned to responding correctly. This, in turn, showed that mice knew what to do to get the reward, yet consciously abstained from it.

Using a computational model, scientists determined that mice exhibit a tendency for dynamic choice, which they believe is a method of learning.

Learning through trial and error

"Mice, surprisingly, use higher-order methods to learn even simple tasks. […] It may seem that the animal makes many mistakes, but through these mistakes, it actually becomes smarter," explains Kuchibhotla.

As he adds, their research on mice has its value. After all, during experiments, rodents don't know what to expect. They don't know when the environment will change or the rules will change. It's natural for them to explore different possibilities. From a human perspective, such behavior may seem unnecessary and time-consuming. This is because, unlike animals, we have verbal communication and, of course, instructions.

However, it is too early to unequivocally interpret the study results. Scientists consider various explanations, such as the possibility that mice occasionally changed the direction in which they turned the wheel because their front paws became tired. Doubts will be dispelled by further experiments in which scientists will examine the activity of mouse brains during decision-making. Interestingly, these are not the first reports suggesting that mice possess intellectual potential. Studies published in 2021 already showed that these rodents learn surprisingly quickly.

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