It’s “further evidence,” we are told, that “they may be self-aware”:
Kohda’s previous research showed that bluestreak cleaner wrasses can pass the mirror test, a controversial cognitive assessment that purportedly reveals self-awareness, or the ability to be the object of one’s own thoughts. The test involves exposing an animal to a mirror and then surreptitiously putting a mark on the animal’s face or body to see if they will notice it on their reflection and try to touch it on their body. Previously only a handful of large-brained species, including chimpanzees and other great apes, dolphins, elephants and magpies, have passed the test.
In a new study, cleaner fish that passed the mirror test were then able to distinguish their own faces from those of other cleaner fish in still photographs. This suggests that the fish identify themselves the same way humans are thought to — by forming a mental image of one’s face, Kohda and colleagues report February 6 in the Proceedings of the National Academy of Sciences. – Betsy Mason, Science News, February 6, 2023
The paper is open access.
Primatologist Frans de Waal
… is quick to point out that failing the mirror test should not be considered evidence of a lack of self-awareness. Still, scientists have struggled to understand why some species that are known to have complex cognitive abilities, such as monkeys and ravens, have not passed. Researchers have also questioned whether the test is appropriate for species like dogs that rely more on scent, or like pigs that may not care enough about a mark on their bodies to try to touch it.
The mixed results in other animals make it all the more astonishing that a small fish can pass. – Betsy Mason, Science News, February 6, 2023
Before we get too deep into the weeds, a great deal depends — as de Waal notes — on how the cleaner wrasse or any other life form uses the type of information that can be found by looking at a picture or into a mirror, as opposed to detecting a sound or smell. Fish might be capable of recognizing their images without being self-aware if doing so is part of a suite of traits they use anyway.
Cleaner wrasses may be self-aware, of course. But just as we would not conclude that a dog who flunks the mirror test is not self-aware, we should not conclude that the fish who passes it is self-aware. We need to know what else the dog or the fish does that implies self-awareness.
It’s not clear that the mirror test is a very good test, for that reason.
You may also wish to read: Mirror, mirror, am I a self? Scientists ponder, how would animals show self-awareness?
A controversy in animal psychology centers on whether or not an animal can recognize itself in a mirror. But a number of scientists are beginning to doubt that the mirror test shows animal self-awareness.
Invented by evolutionary psychologist George Gallup in 1970, the test has been tried on a variety of species, including elephants, dolphins, great apes, dogs, cats, birds, fish, and horses, with varying—and disputed—results. Gallup, for example, doesn’t agree with colleagues that dolphins, elephants and European magpies have passed.
Recently, a fish (the cleaner wrasse), not known for self-awareness, passed the test. One of the researchers took the opportunity to say that he doubts that the test really identifies self-awareness …
No, of course not. It identifies whether a life form can perform certain tasks. That depends on its sensory equipment.
Note: A local wag advises: “Overheard from a tuna surveying a shiny surface, 30 m deep water near the Azores: “Holy mackerel, am I EVER putting on weight.” 😉