Forget everything you thought you knew about animal intelligence – marine biologists have discovered that the humble cuttlefish, a fascinating relative of the squid and octopus, can demonstrate remarkable self-control. In a twist on the famous “marshmallow test,” these cephalopods proved they can wait for a better meal, suggesting complex cognitive abilities similar to those seen in some vertebrates. This finding highlights how sophisticated intelligence can evolve in unexpected ways, perhaps giving these creatures an edge in the competitive ocean environment.
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The Classic Marshmallow Test
The original marshmallow test is a simple experiment designed to measure a child’s ability to delay gratification. Imagine a child in a room with a single marshmallow. They’re told that if they can wait just 15 minutes without eating it, they’ll receive a second marshmallow and get to enjoy both. The ability to wait for a bigger reward later instead of taking an immediate, smaller one is a sign of future planning and self-control. This test, originally from the Stanford marshmallow experiment, has been adapted to study cognitive development.
While you can’t explain rules to an animal, scientists can train them. Animals learn that waiting to eat a readily available food might lead to a better food reward appearing soon after. This adapted test has shown that some animals, including certain primates, dogs, and even crows have passed the marshmallow test, possess this surprising capacity for patience.
Cuttlefish Take the Test
In previous research, cuttlefish were shown to refrain from eating crab meat if they knew a preferred shrimp dinner was coming later. However, researchers wanted to be sure this wasn’t just a foraging tactic related to food availability rather than actual self-control.
Led by behavioral ecologist Alexandra Schnell at the University of Cambridge, a new study designed a more rigorous test for six common cuttlefish (Sepia officinalis). The cuttlefish were placed in a tank with two special chambers, each having a clear door so the cuttlefish could see the food inside. One chamber held a less-favorite snack (raw king prawn), and the other held a highly preferred treat (live grass shrimp).
Diagram showing the experimental tank setup for the cuttlefish marshmallow test
The doors had shapes the cuttlefish recognized: a circle meant the door opened immediately, a triangle meant a delay (10 to 130 seconds), and a square meant it stayed closed.
In the main test, the prawn was behind the ‘instant access’ door (circle), while the prized live shrimp was behind the ‘delayed access’ door (triangle). The catch? If the cuttlefish ate the prawn, the shrimp was instantly removed. In a control test, the shrimp remained inaccessible behind the closed square door.
The results were clear: the cuttlefish in the test condition chose to wait for the shrimp, ignoring the immediate prawn. They were willing to delay gratification for significant periods, up to 130 seconds. This level of patience is comparable to what’s observed in large-brained animals like chimpanzees and crows.
“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,” Schnell stated in 2021.
Learning and Patience Go Together
The experiment also tested the cuttlefish’s learning ability. They were trained to associate a reward with either a grey or a white square. Once they learned which square meant a snack, the researchers switched the association.
Remarkably, the cuttlefish that were quickest to learn and adapt to this change were also the ones who waited longest for the shrimp in the delay-of-gratification test. This suggests a link between flexible learning and self-control in these creatures.
Why Would a Cuttlefish Be Patient?
For animals like parrots, primates, and corvids, delayed gratification is often linked to behaviors like tool use (planning ahead), food caching (saving food for later), or social competence (prosocial behavior benefitting the group).
Cuttlefish, however, are generally solitary, don’t use tools, and don’t cache food. So, why would they evolve this ability to wait?
The researchers propose it’s tied to their unique foraging style. Cuttlefish are masters of camouflage. They spend much of their time hidden, waiting for prey to appear, rather than actively hunting.
A common cuttlefish displays vivid stripe patterns on its body, used for camouflage or signaling
“Cuttlefish spend most of their time camouflaging, sitting and waiting, punctuated by brief periods of foraging,” Schnell explained. “They break camouflage when they forage, so they are exposed to every predator in the ocean that wants to eat them. We speculate that delayed gratification may have evolved as a byproduct of this, so the cuttlefish can optimize foraging by waiting to choose better quality food.”
In other words, being able to wait just a little longer for a truly worthwhile meal might reduce the number of times they have to expose themselves to danger while hunting, making their foraging more efficient and safer.
More Than Just Patient
This adds another layer to our growing understanding of cuttlefish intelligence. Research has also found evidence of “episodic-like memory” in cuttlefish, allowing them to remember specifics like what, where, and when they last ate. More recently, scientists have reported the first observation of cuttlefish forming “false memories,” a phenomenon previously thought to be uniquely human.
These studies suggest that cuttlefish, despite their vastly different evolutionary path and brain structure compared to vertebrates, possess sophisticated cognitive abilities. Future research could explore if this ability to wait for a better reward truly indicates a capacity for planning future events.
This eye-opening experiment reminds us just how much we still have to learn about the incredible minds of animals, especially those living in the complex world beneath the waves.
The study was published in Proceedings of the Royal Society B. You can read more about animal intelligence and cuttlefish cognition in related articles linked above.
