A new test of intelligent cephalopods has reinforced the importance for humans not to underestimate animal intelligence.
Cuttlefish have been subjected to a new version of the marshmallow test, and the results seem to show that there are more things in their strange brains than we knew.
Their ability to learn and adapt, according to researchers, could have evolved to give cuttlefish an edge in the marine-eating or dining-living world.
Testing the marshmallow or evil Stanford 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 they will be allowed to eat both.
This ability to delay gratification demonstrates cognitive skills such as future planning, and was originally carried out to study how human cognition develops; specifically, at what age a human being is intelligent enough to delay satisfaction if it means a better outcome afterwards.
Because it is very simple, it can be adjusted for animals. Obviously, you can’t tell an animal that you will get a better reward if you wait, but you can train to understand it. better food arrives if they do not eat the food in front of them immediately.
Some primates may delay satisfaction, along with dogs, even if it is inconsistent. Corvids have also passed the marshmallow test.
Last year, cuttlefish also passed a version of the marshmallow test. Scientists showed that common cuttlefish (Official sepia) they can refrain from eating crab meat in the morning once they have learned dinner, it’s something they like much more: prawns.
As a team of researchers led by behavioral ecologist Alexandra Schnell of Cambridge University point out in a new article, in this case it is difficult to determine whether this change in feeding behavior in response to prey availability is also governed by an ability to exercise self-control.
So they designed another test, for the usual six 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 rooms there were snacks: a less preferred piece of raw shrimp in one and a lot of much more attractive live grass shrimp.
The doors also had symbols that cuttlefish had been trained to recognize. A circle meant the door would open right away. A triangle meant that the door would open after a time interval of 10 to 130 seconds. And a square, which was only used under control conditions, meant that the door was kept closed indefinitely.
In the test state, the prawn was placed behind the open door, while the live prawn was only accessible after a delay. If the cuttlefish went to fetch the prawn, the prawns would be removed immediately.
Meanwhile, in the control group, the shrimp remained inaccessible behind the square symbol door that would not open.
The researchers found that all the cuttlefish in the test state decided to wait for their favorite food (the live shrimp), but did not bother to do so in the control group, where they could not access it.
“The cuttlefish in the present study were 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 check the level of learning of the six cuttlefish. They were shown two different visual cues, one gray square and one white. When they approached one, the other would be removed from the tank; if they made the “right” choice, they would be rewarded with a snack.
Once they had learned to associate a square with a reward, the researchers changed directions, so the other square became the reward point. Interestingly, the cuttlefish that learned to adapt to this change more quickly were also the cuttlefish that could wait longer to get the prawn reward.
It seems that cuttlefish can exercise self-control, well, but what is not clear is why. In species such as parrots, primates, and corvids, delayed satisfaction has been linked to factors such as tool use (because it requires advance planning), food caching (for obvious reasons). and social competence (because prosocial behavior, such as making sure of everyone) has food – it benefits social species).
Cuttlefish, as far as we know, do not use tools or cache, nor are they especially social. Researchers think this ability to delay satisfaction may have something to do with how cuttlefish are fed for food.
“Cuttlefish spend most of their time camouflaging themselves, sitting and waiting, marked by short periods of eating,” Schnell said.
“They break up camouflage when they are eaten, so they are exposed to all ocean predators who want to eat them. We speculate that delayed satisfaction may have evolved as a byproduct of this, so cuttlefish may optimize the food waiting to choose a better quality food “.
It is a fascinating example of how very different lifestyles in very different species can lead to similar behaviors and cognitive abilities. The team noted that future research should try to determine if cuttlefish are able to plan for the future.
The team’s research has been published in Proceedings of the Royal Society B.