If you’ve ever been scuba diving in the ocean, you’ve probably come across schools of fish. Unlike the majority of youths, fish enjoy being in schools. They spend not just weekdays in schools, but also weekends. That’s because schools promote learning, and fish know they have a lot of catching up to do.
But don’t take my word for it. Just ask a group of researchers in Germany who recently showed that two types of fish, cichlids and stingrays, can perform simple addition and subtraction. They can add and subtract numbers from one to five, which means that they’re almost ready to run the cash register at McDonald’s. Trust me, it’s only a matter of time before you’ll be buying a fish sandwich from a fish.
According to a ScienceDaily report, scientists have long known that cichlids and stingrays, like humans, can distinguish small quantities without counting. If you’ve invited three people to dinner at your home and four people show up, you don’t have to count them to know that an extra person is there. Cichlids and stingrays can be trained to do something similar. They might even call an Uber for the uninvited guest.
The research group at University of Bonn’s Institute of Zoology conducted tests to show that these fish can even calculate. “We trained the animals to perform simple additions and subtractions,” said Dr Vera Schluessel, who led the research group. “In doing so, they had to increase or decrease an initial value by one.”
I cannot over-emphasise how impressive it is that fish can perform simple addition and subtraction. Trust me, the average elementary school child would not be able to do this—perform simple addition and subtraction while fully submerged in water.
Arithmetic is hard enough without having to do it underwater.
You’re probably wondering how the fish were able to demonstrate their ability to add and subtract. Well, the researchers showed the fish geometric shapes and conveyed their instructions through colours. Three blue shapes meant that the fish needed to add one, whereas three yellow shapes meant the fish needed to subtract one. After viewing three blue squares, for example, the fish were shown a picture of four squares, as well as a picture of two squares. If the fish swam to the picture of four squares, they received an ‘A’ on the test and could graduate from school.
Actually, if the fish swam to the right picture, they were rewarded with food. And according to ScienceDaily, if they swam to the wrong picture, “they went away empty-handed.” (This is quite surprising to me. I did not realise that some fish have hands.)
After taking an entire course in math from the researchers, the fish learned the meaning of blue (add one) and yellow (subtract one). But the big question was whether they could apply this knowledge to new tasks.
“To check this, we deliberately omitted some calculations during training,” Schluessel explained. “Namely, 3+1 and 3-1. After the learning phase, the animals got to see these two tasks for the first time. But even in those tests, they significantly often chose the correct answer.”
Even when the researchers used different sizes and types of shapes, the fish were able to find the correct answers. Schluessel called it “a feat that requires complex thinking skills.”
What the research shows, she said, is that humans tend to underestimate other species, especially non-mammals. Indeed, most people who keep fish in aquariums have a very low bar in judging their pets’ intelligence.
“Did you see that?” they exclaim. “My fish spotted me and swam to the surface, knowing they were about to get fed. They’re so intelligent.”
What they don’t realise is that the fish are much smarter, saying to themselves: “Did you see that? Our owner had one pimple on his nose yesterday and today he has three!”
