Cephalopod passed cognitive test designed for human children

The cuttlefish has been put through a new version of the marshmallow test, and the results seem to show that there is more going on in their strange little brains than we knew.

According to the researchers, their ability to learn and adapt may have evolved to give the cuttlefish an edge in the cutthroat marine world in which it lives.

The Marshmallow Test, or Stanford’s Marshmallow Experiment, is pretty straightforward. A child is placed in a room with a marshmallow. They are told that if they manage not to eat the marshmallow for 15 minutes, they will get a second marshmallow and be allowed to eat both.

This ability to delay gratification demonstrates cognitive abilities such as future planning, and it was originally conducted to study how human cognition develops; more specifically, at what age is a human smart enough to delay gratification if it means a better outcome later on.

Because it’s so simple, it can be adjusted for pets. Obviously, you can’t tell an animal that it will get a better reward if it waits, but you can teach it to understand that. best food arrives if they don’t eat the food in front of them right away.

Some primates can delay gratification, with dogs, although inconsistently. The corvids also passed the marshmallow test.

Last year the cuttlefish also passed a version of the marshmallow test. Scientists have shown that the common cuttlefish (Sepia officinalis) can refrain from eating a crab meat meal in the morning once they have learned that dinner will be something they like much better – shrimp.

As a team of researchers led by behavioral ecologist Alexandra Schnell of the University of Cambridge points out in a new article, however, in this case, it is difficult to determine whether this change in foraging behavior in response to the Availability of prey was also governed by a capacity. exercise self-control.

So they designed another test, for six common cuttlefish. The cuttlefish were placed in a special tank with two closed chambers that had transparent doors so that the animals could see inside. In the bedrooms were snacks – a less popular piece of raw king prawn in one and much more appealing live grass prawns in the other.

The doors also bore symbols that the cuttlefish had learned to recognize. A circle meant the door would open right away. A triangle meant the door would open after a time interval of between 10 and 130 seconds. And a square, used only under control conditions, meant that the door remained closed indefinitely.

Under the test conditions, the shrimp was placed behind the open door, while the live shrimp was only accessible after some time. If the cuttlefish opted for the shrimp, the shrimp was immediately removed.

Meanwhile, in the control group, the shrimp remained inaccessible behind the square symbol door that did not open.

The researchers found that all of the cuttlefish in the test condition decided to wait for their favorite food (live shrimp), but didn’t bother to do so in the control group, where they couldn’t access it. .

“The cuttlefish in the present study were all able to expect the best reward and tolerated delays of up to 50-130 seconds, which is comparable to what we see in large-brained vertebrates such as chimpanzees, crows and parrots, ”Schnell said.

The other part of the experiment was to test the learning ability of the six cuttlefish. They were shown two different visual clues, a gray square and a white. As they approached one, the other was removed from the tank; if they made the “right” choice, they would be rewarded with a snack.

Once they learned to associate a square with a reward, the researchers changed the signals so that the other square now became the reward signal. Interestingly, the cuttlefish that learned to adapt to this change the fastest were also the cuttlefish that were able to wait longer for the shrimp reward.

Seems like the cuttlefish can exercise self-control, okay, but what’s not clear is why. In species such as parrots, primates and corvids, delayed gratification has been linked to factors such as tool use (as this requires planning in advance), food caching (for obvious reasons) and social competence (because prosocial behavior – like making sure everyone has food – benefits social species).

The cuttlefish, as far as we know, does not use any tools or food cache, and is not particularly social. Researchers believe that this ability to delay gratification may instead have something to do with how the cuttlefish forages for food.

“Cuttlefish spend most of their time camouflaging, sitting and waiting, punctuated by brief periods of foraging,” said Schnell.

“They break the camouflage when they feed, so they’re exposed to whatever predators in the ocean want to eat them. We believe that delayed gratification may have evolved as a byproduct of that, so the cuttlefish can optimize foraging while waiting to choose a better quality.

It’s a fascinating example of how very different lifestyles in very different species can result in similar behaviors and cognitive abilities. Future research should, according to the team, try to determine whether cuttlefish are indeed capable of planning for the future.

The team’s research has been published in Proceedings of the Royal Society B.