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Fish can learn to steer. That message and the accompanying video made it to the world press early this month. It involved an experiment in which researchers followed a pair of goldfish with a camera. The camera tracked their movement in an aquarium on wheels that was controlled by the movement of the fish.

The experiment was run by a research group at Ben-Gurion University of the Negev (Israel). The study suggests that the ability to navigate is universal and that goldfish possess the cognitive ability to learn a complex task in an environment totally different from their own.

The experiment is not particularly original. Studio Diip, a Dutch firm that specializes in applications for image recognition software, had already conducted a similar experiment in 2014.

That experiment also got publicity in the world press at the time. It led to an enthusiastic and humorous reaction from Tesla’s Elon Musk, who fancied the idea of a future with goldfish behind the wheel. We were wondering how colleagues in the field see this experiment. Michael Richardson, professor of Evolutionary Developmental Zoology at Leiden University in The Netherlands, has his views on this.

What did you think when you learned about the experiment?

“That it is amazing. I could hardly believe it. The principle is very simple. No brain signals are recorded, just the swimming motion in the aquarium. It seems that the fish is able to discover that it is actually moving that thing on wheels by its own movement. The fish seem to learn from their own act of swimming. Possibly spurred on by a small reward they receive at the end of the course.”

Michael Richardson

It’s a bit reminiscent of a Pavlov response.

“In a sense, at least as far as the reward and conditioned reflex aspects are concerned.”

What is the aim of the experiment?

“We want to understand human behavior and find out if any behavior is inheritable. Certain fish species are well suited to that. Our research group in Leiden is also working on this. In short, it comes down to breeding fish from a batch of eggs and studying the different character traits of the fish that hatch. Some fish are fearful and others are confident as they move through the water. Is personality inheritable or is it learned? -That is the question.”

The age-old debate of nature versus nurture!

“Indeed. Some character traits are formed by upbringing, others are genetically predetermined. We now more or less assume that the influence of heredity and environment is fifty-fifty. We hope to gain more insight into this through research on fish.”

Why were goldfish used for this experiment?

“We use zebrafish for our research, which, like goldfish, belong to the category of bony fish. We also use cameras to see how the fish swims, changes direction, is stressed or relaxed whether it is bold or timid and so on. Fish have individual personalities. From fish eggs come fish, each with its own personality. You have the more assertive types, and fish that are more stressed, who hide in the dark, for example. So, fish are a good model for testing levels of stress and personality. You could also find out how to influence stress this way.”

Do fish know what stress is too?

“They certainly do. Zebrafish have the same cortisol stress hormone as humans. Humans and zebrafish have the same stress mechanism. Yeah, yeah, there are lots of similarities between human and fish behaviors.”

You can use other kinds of animals, right?

“Bony fish, such as the zebrafish and goldfish, make good animal models. Fish grow very quickly and reach adulthood within a few months. So, there is a fast generation time. Generational behavioral studies in humans can easily take 40 years. Moreover, the genome of the zebrafish is known and does not differ that much from other experimental animals, such as mice and rats. As such, this fish provides good comparison material to humans.”

“It is also cheaper to carry out experiments with fish. Another advantage is that a small amount of space is enough for these test animals. Fish swim around in the water and it is easy to analyze them. If you were to take reptiles, you would need huge equipment. Mammals need a host of permits, in part because these tests are a touchy subject in society.”

Isn’t the hypothesis advanced by the ‘goldfish researchers’ that navigating is species-independent a tad audacious?

“At first glance, that might be the case because it only concerns one species. But I think they mean to say that it covers all bony fishes, which implies that, for example, the phenomenon of stress goes way back in evolution.”

(Photo: zebrafish)

Read also about other research at the Ben Gurion University: Ordinary lamps can now be used to eavesdrop on conversations remotely