The report said the archerfish were chosen because they have the ability to target images.
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Archerfish spit a jet of water to knock down prey in branches above water.
Each pair contained the familiar face and one odd one and the familiar face was moved around the screen, to ensure the fish weren’t simply spitting in a direction they had grown to like. Scientists first trained the fish to spit on a particular face displayed on a monitor.
“When humans recognize a human face, it provides not only information about the identity of the person but also a whole host of other information, such as a person’s gender, age, health”, Newport said.
Next, researchers mixed that face with as many as 44 others. In order for us to tell people apart, therefore, we need to look for distinguishing features.
But many believe fish to be incapable of doing so due to their tiny brains.
The study was published in the journal Scientific Reports.
“This does start to suggest that there’s nothing special about human faces, and that they can be treated as any other object and still recognized”, Dr. Newport, the Marie Curie Research Fellow in the Department of Zoology at Oxford University, told The Washington Post. It is not a matter of having or not facial recognition brain structures because in this case, archerfish do not have the same brain structure than humans, and they still can recognize with favorable rates.
This experiment shows that complex brains are not necessary in order to recognize faces.
The fish were then presented with the learned face and a series of new faces and were able to correctly choose the face they had initially learned to recognise.
Dr Newport capitalised on the archerfish’s ability to spit out jets of water. How does the fish let researchers know which face it is choosing?
Dr Ulrike Siebeck from the UQ School of Biomedical Science (SBMS) said the findings suggested that human facial recognition was driven by learned behaviour, rather than innate processes facilitated by specialized cells in the human brain.
That’s where fish come in: They don’t have anything like this structure within their (relatively) simple brains. The brain of the archerfish lacks this region, yet, it can recognize a familiar face 80 percent of the time.
The fish in the study were able to pick out (read: spit on) the specific face 81% of the time in the first experiment, and 86% of the time in the second experiment, once the researchers standardized facial color and brightness. This research found that these fish could recognize facial differences among their own species with the aid of ultraviolet wavelengths.
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Newport says, “Fish have a simpler brain than humans and entirely lack the section of the brain that humans use for recognizing faces”.
