The myth that goldfish only have a three-second memory may be an unfair view of goldfish’s mental abilities. A new study shows that some fish can recognize themselves in photographs. That means joining a fairly exclusive club of animals known to have a degree of self-awareness.
While it may seem like a basic skill to us, self-awareness shows that animals are capable of carrying out advanced mental processes. Testing with a mirror is most common. Many animals, such as dogs, react as if they are another person in the mirror, but some can recognize that what they are looking at is themselves. Apes, dolphins, elephants, and some birds have passed the test, and it takes even a human child about 18 months to figure it out.
A few years ago, a team of scientists investigated whether a fish species called cleaner wrasse could pass the Miller test. They attached what appeared to be parasites to the fish’s throat and placed a mirror in the tank. And sure enough, many animals saw the mark in their reflection and scraped it down their throats. This indicates that you are aware that you are looking at yourself. This was confirmed by marking the mirror itself or other fish in adjacent tanks, but no fish scraped off the marks.
In a new study, researchers wanted to go a step further and see if the fish could recognize themselves in photographs. One is a picture of yourself, another is an unfamiliar fish, and the other is a different fish with your face on it. Another photo shows an unfamiliar face on my body.
Cleaner wrasses are territorial and will attack intruders. In this case, they attacked pictures of unfamiliar fish, but not pictures of themselves. They also didn’t attack a photo of another body’s face, but attacked a stranger’s face photo on their own body. This indicates that fish recognize facial features more than body features.
These photographic tests show that fish not only recognize themselves by matching their movements in the mirror, but can actually build a mental model of their own face. Only fish trained in can pass the photographic test, giving them time to build these mental images.
Another possible explanation was to investigate that the team presented the fish with photographs showing throat marks, as the fish came to view photographs of themselves as close companions. And sure enough, 6 of the 8 fish rubbed their throats to clear their marks, a behavior they didn’t display when shown pictures of themselves without marks or of other fish with marks. .
“This study is the first to show that fish have an inner sense of self,” said Masanori Kanda, the study’s principal investigator. “Since the target animals are fish, this finding suggests that nearly all social vertebrates also have this higher sense of self.”
A study was published in a journal PNAS.
Source: Osaka Metropolitan University
