A new piece of evidence has landed that shows fish are smarter than what humans give them credit for. A wise lesson in humility for everyone as a new study finds that fish can be trained to recognise human faces up to an incredibly high 81% accuracy rate despite the fact that they lack a neocortex, which is known to be involved in higher sensory perception functions.
The study published in Scientific Reports shows that a tropical fish—the archerfish—spits out little jets of water to stun prey and can be trained to recognise human faces with surprising accuracy in order to receive a food reward. The archerfish can distinguish 1 face from 44 others smashing up to 81% accuracy. The fish could even distinguish the face when all of the images were controlled for head shape, colour, and brightness.
While there are two rival theories of how humans recognise faces exist involving recognition, relying on specialised neocortical circuitry, and recognition as a learned expertise, relying on general object recognition pathways, it appears that animals without a neocortex are able to do the same thing. The long standing arrogant belief that this ability to recognise and distinguish between human faces is possessed only by intelligent creatures like humans and primates because of our larger brain size—and not something that fish with a ‘tiny simple brain’ without a neocortex could do—has just been smashed out of the water.
A quick side note: For those who love quoting that fish only have a three-second memory, this has been rebutted over and over.
How Fish Can Recognise Human Faces
The neocortex exists in mammals and accounts for about 76% of our brain’s volume. It is involved in higher functions such as sensory perception, generation of motor commands, spatial reasoning, conscious thought, and language. As Vox reports, the ability for humans to recognise individual faces in amongst the collection of hundreds of faces was thought for a long time to be one of sophisticated brain machinery, involving a combination of perception and memory. Brain scans show that part of our neocortex known as the fusiform gyrus becomes activated when we look at faces, and when people with damage to the fusiform gyrus lose their ability to recognise faces, it is known as a disorder called prosopagnosia.
I think it’s really fascinating that [fish] have these supposedly simple brains in terms of the actual structure of it, but they’re still able to use them for really complicated tasks, and we probably just don’t give them enough credit.
The study was led by Cait Newport of Oxford University who wanted to explore whether animals without a neocortex can learn to recognise human faces. Human facial recognition has actually been previously demonstrated for birds, who have always been said to lack a neocortex. Scientists confirmed that birds actually have neocortical-like functioning, but that it’s done differently as a result of convergent evolution. It’s even thought that this may actually give birds certain cognitive advantages over mammals, and certainly provides weight to other animals—who do not have a neocortex—having greater intelligence than humans give them credit for.
Admittedly, it can be difficult to be 100% certain with animal studies as we can only view their behaviour and not their inner lives. But considering of the estimated 62,000 species of vertebrates on the planet, half of them are fish, we should be doing more to understand these amazing animals instead of assuming that they are dumb, simple creatures. Our treatment of fish, currently, is unquestionably abusive and predatory at best, where the ocean is treated as a wasteland for our trash and like some infinite food source that never once considers the interests of trillions of complex lives and supporting ecosystems.
The fact that the discrimination of individuals based on facial features is not unique to humans and the evidence that the archerfish can discriminate human faces without having any obvious selection pressure, suggests that the visual systems fish are capable of sophisticated recognition tasks.
In hindsight, it’s not surprising as so many behaviours are fundamental to the survival of a wide range of species who reply on accurate vision-based object recognition. This recognition involves things like detecting predators, mate selection, and feeding. Perhaps this finding helps add some additional weight to dismantling the old argument that because fish do not have feelings, they can’t possibly feel pain. There is growing extensive evidence of fish behavioural and cognitive sophistication and pain perception that suggests the best practice would be to lend fish the same level of protection as any other vertebrate who values their life.
It’s about time that we started respecting the ocean and its diverse inhabitants as the complex animals that they are. It’s about time we left fish off our plates and instead consume plant-based foods, which cause far less harm to animals, the environment, and our health.
Sources: Vox, IFLScience, ScienceDaily, MFA, io9.
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