An international team of scientists reveals that a species of tropical fish can recognize human faces. For the first time, scientists from the University of Oxford in the UK and the University of Queensland in Australia showed that archerfish learned and familiarized faces with impressive accuracy despite the lack of complex brains.
The findings published on June 7 in the journal Scientific Reports state that archerfish, known to shoot jets of water to bring down their prey, achieved this difficult task despite lacking the sophisticated visual cortex of primates, which allows primates to tell the tiny differences between unique facial features of different faces. The team found that the fish recognized one face from up to 44 other faces, proving that the fish species have visual discrimination skills.
The researchers showed the tropical fish with two photos of human faces and they trained the fish to spit water jets on one facial photograph. A series of other facial pictures were then shown but the archerfish still recognized the chosen photo, even when the visible features like head shape and color were standardized in the photos.
“Fish have a simpler brain than humans and entirely lack the section of the brain that humans use for recognizing a face,” explains study author Cait Newport from Oxford University. “Despite this, many fish demonstrate impressive visual behaviors and therefore make the perfect subjects to test whether simple brains can complete complicated tasks.”
It is estimated that the fish were right 81 percent of the time when they had to identify the chosen photo from 44 other photos. The fish were right 86 percent of the time when they had to choose the learned photo which has obvious facial features’ brightness and color removed from it.
“The fact that archerfish can learn this task suggests that complicated brains are not necessarily needed to recognize human faces,” adds Newport. “Humans may have special facial recognition brain structures so that they can process a large number of faces very quickly or under a wide range of viewing conditions.”