Research recently carried out by my team suggests that fish may be self-aware. A certain species of fish recently passed the well-known mirror test.
This is a test that demonstrates self-recognition in animals. Only a few animals, such as humans, apes, dolphins and some birds, can recognize themselves in a mirror. And only these animals, capable of self-recognition, will attempt to remove marks placed on their skin after noticing them in the reflection. This ability suggests a level of higher intelligence and awareness. This is not shown by children until around 18 months. Until now, no fish has demonstrated the ability. But our experiments show the fish in question will scrape up against hard surfaces to remove marks placed on its body by our researchers after viewing itself in a mirror. The behaviors we observe leave little doubt that this fish behaviorally fulfills all criteria of the mirror test as originally laid out. The fish in our study never attempted to remove the marks when no mirror was present or when the marks were just placed on the mirror. Unmarked fish also did not attempt to remove marks from themselves when interacting with a marked fish on the other side of a window. These results show either that fish are self-aware or that the mirror test, which is considered to be the gold standard test used to denote higher intelligence, may be flawed.
What is less clear is whether these behaviors should be considered as evidence that fish are self-aware, even though in the past these same behaviors have been interpreted as self-awareness in so many other animals. Depending on your position, you might reject the interpretation that these behaviors in a fish satisfy passing the test at all. But on what objective basis can you do this when the behaviors they show are so functionally similar to those of other species that have passed the test?
Results from our research raise more questions than answers. What if self-awareness develops like an onion, building layer upon layer rather than appearing all at once? Perhaps in order to explore self-awareness further, we should stop looking at responses to the mirror as a decisive test. Only with a richer theory of the self and a larger test battery will we be able to determine all of the various levels of self-awareness, including where exactly fish fit in.