Study not only demonstrates that archerfish have impressive pattern discrimination abilities, but also provides evidence that a vertebrate lacking a neocortex can nonetheless do so to a high degree of accuracy.
Distinguishing between human faces is a surprisingly difficult task but archerfish are nonetheless able to tell one human face from another despite not having a neocortex, the most recently evolved part of the human brain, governing sensory perception and language, a team of scientists from Oxford and Australia’s University of Queensland have demonstated.
Archerfish, a tropical species best known for spitting pressurised water jets to shoot prey out of the air, were taught to spit at pictures of a human facedisplayed on a computer monitor suspended over their aquarium. The researchers then tested whether the fish would recognise, and spit at, the familiar face among 44 new ones in exchange for a food reward. The fish got it right more than 80% of the time.
“We were pleasantly surprised at the speed at which the fish learnt as well as their high degree of accuracy,” said study co-author Cait Newport of the Oxford University’s department of zoology, told the Guardian.
Fish present an interesting example as they can use colour patterns for recognition which are additionally affected by changes in water quality and lighting. Because different wavelengths are attenuated unequally in water, some colours within a pattern are affected more than others.
It is possible that the perceived complexity of human facial recognition may simply be an anthropogenic point of view and in fact other animals must also perform similarly complex pattern discrimination tasks under highly demanding conditions.