Humans can recognize their faces in mirrors and photos almost automatically. Ongoing research at Metropolitan University in Japan suggests that fish have the same ability. Being able to recognize your reflection or being self-aware, is an ability usually tied to intelligent animals, such as chimpanzees or humans. Finding this ability in fish suggests that self-awareness might be more common than scientists previously thought.
Previous research at Metropolitan University demonstrated that Bluestreak Cleaner Wrasses can pass a self awareness test using a mirror. To conduct the test, scientists expose an animal to a mirror for a long period of time. Once the animal gets acquainted with its reflection, scientists add a mark somewhere on its body. If the subject were to be self-aware, it would start to touch that spot on its body in hopes of getting rid of that mark. Before this research, only large-brained animals such as apes, dolphins, elephants, and magpies have passed the test.
Failing the mirror test should not be indicative of lack of self awareness. Other animals thought to have large brains, such as monkeys and ravens have not passed. Scientists also wonder if this is an appropriate test for animals who rely on other senses, or ones who don’t care about how they look. As a result of this, it makes it more surprising that a fish can recognize itself.
To conduct the research on the fish, a team of scientists at Metropolitan University exposed the Bluestreak Cleaner Wrasse to a mirror for a week. Then, the scientists would inject a brown spot to imitate a parasite. When the fish saw their reflection, they would use the surrounding objects to try and get it off. Similarly, when fish were shown a picture of themselves and a picture of another fish, the fish acted as if the picture was not them, and was a complete stranger. They started to act more aggressive towards it, but did not acknowledge the picture of themselves as if it was their reflection.
Fish and other animals likely learn to identify themselves in a mirror by seeing that the movement of the creature in the mirror matches their own. Since the Cleaner fish were also able to recognize their own face in images, scientists suggest that fish and other animals may be able to develop a mental picture of their own appearance.
The research group at Metropolitan University continues to try and figure out what is going on inside the heads of these fish. They also hope to branch out to other common research fish, such as the Three-Spined Stickleback. This data has helped equalize the playing field when it comes to understanding the brain power of different animals, and can be used to open doors to other lanes of vertebrate research.
[Source: Science News Explores]