Can Cuttlefish Exert Self-Control? Here's How It Performed in This Marshmallow Experiment

Cuttlefish, chunky squid-like animals with eight limbs, are said to be able to prolong gratification and exercise self-control for a better reward, experts say.

(Photo : Image by manseok Kim from Pixabay )
The common cuttlefish can be trained to wait significant spans of time for food. It could likewise delayed gratification when it led to a food item of higher quality and were able to maintain delays for periods of up to 50 to 130 seconds.

This fascinating research is the first to demonstrate a connection between self-control and intelligence in a species other than humans and chimps. Experts published the study in the Proceedings of the Royal Society B this week, Eurekalert said.

Such results could help scientists better explain the evolution of intelligence, which is still a work in progress.

Cuttlefish's Delayed Gratification: What's New?

This marine mollusk, also known as Sepia officinalis, may not be the cutest cephalopod in town. But it's one of the most interesting species. The cuttlefish is best known for its tendency to blend in with its surroundings in the water, resisting predatory attention.

Cuttlefish may also exhibit self-control by delaying reward in order to capture higher-quality prey, according to researchers.

Lead author Alexandra Schnell, a researcher at the University of Cambridge, found this surprising discovery.

"Finding evidence for self-control in a cuttlefish, an invertebrate that diverged from the vertebrate lineage over 550 million years ago, is surprising," Schnell told Inverse.

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How Researchers Did The Stanford Marshmallow Test

Researchers used a modified version of the Stanford marshmallow test on six cuttlefish in an aquarium setting. They have the option of eating an immediate reward (one marshmallow) or waiting for a slower but better reward (two marshmallows). According to Schnell, they adapted the said test that it was "more cuttlefish friendly."

Experts gave invertebrates chambers that were labeled with numerous visual clues in the form of shapes. For example, one cue meant that the door would open when food was placed in that chamber, while another suggested that there would be a wait until the door opened when food was placed in that chamber. Even though researchers had dropped the food in the chamber and then opened the door, an additional plastic layer stopped the cuttlefish from consuming the reward.

The cuttlefish immediately hopped in as soon as they saw the food in the chambers when scientists allowed the species to adapt to the environment. They finally learned that each section had its own set of rules. The mollusks finally started entering the "unobtainable" chamber because they knew they would never gain access to the food.

After the introduction, researchers placed the cuttlefish to the test in two chambers: in the "immediate" section, they were given their second-preference food, and in the "wait" chamber, they were given their first-preference food. These requirements were repeated in the control setting, except that the delay chamber was the unobtainable chamber.

Overall, the cuttlefish delayed gratification as it contributed to a higher-quality prey item. Researchers said per ArsTechnica that the fish could sustain delays for up to 50 seconds to 130 seconds.

What Did Researchers Conclude?

Schnell said previous studies indicated that certain primates and birds displayed this high degree of self-control because they were social animals with many interactions and resources.

She found out that these animals could not forage or kill at a given time in order to create tools or wait until their companion had fed. "However, cuttlefish are not social and do not use tools," says the author.

Instead, she hypothesized, self-control may have developed in cuttlefish to improve production. Cuttlefishes are considered "a juicy meal," according to Schnell. As a result, these animals spend extended periods camouflaged and nearly motionless on preventing being spotted by predators. When cuttlefish forage, this motionless activity is disturbed.