Science Snippets: Cephalopods More Intelligent than Human Children?

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I have mentioned previously in this space the aptitude of non-human species to survive and thrive. I have also described the short attention span of humans being compared to goldfish. This video presents another example of a surprising case of cognition in non-human animals.

The headline at Science Alert on 10 January 2025 provides a stunning example of the cognitive ability of cephalopods: Cephalopods Pass Cognitive Test Designed For Human Children. According to the Merriam-Webster online dictionary, a cephalopod is “any of a class (Cephalopoda) of marine mollusks including the squids, cuttlefishes, and octopuses that move by expelling water from a tubular siphon under the head and that have a group of muscular usually sucker-bearing arms around the front of the head, highly developed eyes, and usually a sac containing ink which is ejected for defense or concealment.” In other words, squids are more intelligent than your child.

The article at Science Alert includes this information about cephalopods: “Back in 2021, a test of cephalopod smarts reinforced how important it is for us humans to not underestimate animal intelligence.

Cuttlefish were given a new version of the marshmallow test, and the results may demonstrate that there’s more going on in their strange little brains than we knew.

Their ability to learn and adapt, the researchers said, could have evolved to give cuttlefish an edge in the cutthroat eat-or-be-eaten marine world they live in.

The marshmallow test, or Stanford marshmallow experiment, is pretty straightforward.

A child is placed in a room with a marshmallow. They are told if they can manage not to eat the marshmallow for 15 minutes, they’ll 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; specifically, at what age a human is smart enough to delay gratification if it means a better outcome later.

Because it’s so simple, it can be adjusted for animals. Obviously, you can’t tell an animal they’ll get a better reward if they wait, but you can train them to understand that better food is coming if they don’t eat the food in front of them straight away.

Some primates can delay gratification, along with dogs, albeit inconsistently. Corvids, too, have passed the marshmallow test.” Corvids are birds in the crow family, known for their intelligence.

“In 2020, cuttlefish also passed a version of the marshmallow test. Scientists showed that common cuttlefish … can refrain from eating a meal of crab meat in the morning once they have learnt dinner will be something they like much better – shrimp.

However, as a team of researchers … pointed out, in this case it was difficult to determine whether this change in foraging behavior in response to prey availability was also being governed by an ability to exert self-control.

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

The doors also had symbols on them that the cuttlefish had been trained to recognise. A circle meant the door would open straight away. A triangle meant the door would open after a time interval between 10 and 130 seconds. And a square, used only in the control condition, meant the door stayed closed indefinitely.

In the test condition, the prawn was placed behind the open door, while the live shrimp was only accessible after a delay. If the cuttlefish went for the prawn, the shrimp was immediately removed.

Meanwhile, in the control group, the shrimp remained inaccessible behind the square-symbol door that wouldn’t open.

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

The other part of the experiment was to test how good the six cuttlefish were at learning. They were shown two different visual cues, a grey square and a white one.

When they approached one, the other would be removed from the tank; if they made the “correct” choice, they would be rewarded with a snack.

Once they had learnt to associate a square with a reward, the researchers switched the cues, so that the other square now became the reward cue.

Interestingly, the cuttlefish that learnt to adapt to this change the quickest were also the cuttlefish that were able to wait longer for the shrimp reward.

That seems like cuttlefish can exert self-control, all right, 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 (because it requires planning ahead), food caching (for obvious reasons) and social competence (because prosocial behavior – such as making sure everyone has food – benefits social species).

Cuttlefish, as far as we know, don’t use tools or cache food, nor are they especially social. The researchers think this ability to delay gratification may instead have something to do with the way cuttlefish forage for their food.”

I now turn to the peer-reviewed paper. Titled Cuttlefish exert self-control in a delay of gratification task, it was published 10 March 2021 in Proceedings of the Royal Society B: Biological Sciences. Created by five scholars, the peer-reviewed, open-access paper includes this information in the Abstract: “The ability to exert self-control varies within and across taxa. Some species can exert self-control for several seconds whereas others, such as large-brained vertebrates, can tolerate delays of up to several minutes. Advanced self-control has been linked to better performance in cognitive tasks and has been hypothesized to evolve in response to specific socio-ecological pressures. These pressures are difficult to uncouple because previously studied species face similar socio-ecological challenges. Here, we investigate self-control and learning performance in cuttlefish, an invertebrate that is thought to have evolved under partially different pressures to previously studied vertebrates. To test self-control, cuttlefish were presented with a delay maintenance task, which measures an individual’s ability to forgo immediate gratification and sustain a delay for a better but delayed reward. Cuttlefish maintained delay durations for up to 50–130 s[econds]. To test learning performance, we used a reversal-learning task, whereby cuttlefish were required to learn to associate the reward with one of two stimuli and then subsequently learn to associate the reward with the alternative stimulus. Cuttlefish that delayed gratification for longer had better learning performance. Our results demonstrate that cuttlefish can tolerate delays to obtain food of higher quality comparable to that of some large-brained vertebrates.”

Humans, of course, are large-brained vertebrates. Our large brains allow us to accomplish many surprisingly difficult tasks. We lack morphological protection. We’re not particularly fast. Considering our innate inability to protect ourselves from other organisms, our large brains carry a heavy load in protecting us and also in allowing us to kill and eat other animals. The information presented in this peer-reviewed article indicates that we are not the only species capable of such difficult tasks. That other species are capable of complex tasks comes as no surprise. Indeed, this is yet another indicator that we are one.