Cuttlefish Shows Off Its Smarts By Passing Cognitive Test Meant For Human Kids

Updated September 6, 2021

There are lots of ways that humans are different from the rest of the animal kingdom: we have those mighty opposable thumbs, for example — mind you, so do many other animals, especially our primate relatives like gorillas and chimpanzees — and we walk around on our hind legs all the time. But what has really separated us is our big brains.

Humans are, without a doubt, super smart animals. We can do long division, send electrons from one place to another, and some of us can even parallel park — not me, personally, but I've seen it done before.

But there are other smart animals out there that should really have us re-thinking our high esteem of ourselves, and we can probably add another to that list now.

There is, in psychology, a test called the marshmallow experiment.

Reddit | lobsterwithcrabs

And yes, it involves marshmallows. It's deceptively simple in nature. In the experiment, a child is offered a choice: eat a marshmallow right now, or wait 15 minutes and get two marshmallows to eat.

Yes, it seems rather obvious that two marshmallows are better than one, but that's to adults. In children, the experiment shows their ability to plan for the future and strategically delay their gratification, which indicates a certain stage in their cognitive development.

It's also an experiment that some animals have passed before, including some primates, corvids, and like the Milkbone model above, dogs (although they're not 100% consistent at it, as any dog trainer can attest).

Scientists also recently managed to find out if a cuttlefish can pass the marshmallow test, and the answer was a resounding yes.

Wikimedia | https://commons.wikimedia.org/wiki/File:Georgia_Aquarium_-_Cuttlefish_Jan_2006.jpg

Well, it was a version of the marshmallow test, anyway. Obviously aquatic life has little interest in gooey sugary pillows. Instead, for their test, researchers led by University of Cambridge behavioral ecologist Alexandra Schell used a more pedestrian meal of king prawn in place of the first marshmallow, and the much-preferred live shrimp in place of the second marshmallow.

But how the heck did they get the cuttlefish to show whether they could delay gratification?

Well, it involved a fair amount of training ahead of time, as well as a specially designed tank.

Wikimedia Commons | Hans Hillewaert

The researchers had six cuttlefish in the experiment, which they trained to recognize symbols on little transparent doors over a pair of chambers in the tank. A door with a circle on it, for example, would open right away, while a door with a triangle on it would take anywhere from 10 to 130 seconds to open. A third door with a square on it, indicating it wouldn't open at all, was only used in the control condition.

The cuttlefish could see behind the doors — where the food was — with the king prawn behind that door with a circle on it, and the tasty shrimp behind one of the other doors. If the cuttlefish went for the king prawn, the shrimp was taken away; in the control group, the cuttlefish couldn't get at the shrimp at all.

When it came right down to it, the cuttlefish really wanted that shrimp and were willing to wait for it.

And they were able to tell when they'd get it, as the control group went right ahead and ate that prawn when they realized they weren't getting the shrimp.

"Cuttlefish in the present study were all able to wait for the better reward and tolerated delays for up to 50-130 seconds, which is comparable to what we see in large-brained vertebrates such as chimpanzees, crows and parrots," Schnell said in a press release.

The researchers also tested the cuttlefish's ability to learn.

For that, the cuttlefish learned to associate one visual cue with a food reward, and then the researchers switched it up and changed the visual cue with the reward — and there was some unexpected overlap between the two.

"The cuttlefish that were quickest at learning both of those associations were better at exerting self-control," Schnell said.

But their performance wasn't 100%. "You do get the impatient ones," Schnell told Hakai Magazine. "There was one cuttlefish that would squirt me with her siphon repeatedly until I would come over to feed her. They have so much character."

The research was published in The Royal Society.

h/t: EurekAlert, Hakai Magazine

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