When talking of emotions and decision-making capabilities in the animal kingdom, we,generally, first turn to mammals like primates (chimpanzee, ape, humans etc) but rarely of fishes. However, a recent study suggests that cuttlefish may have similar controlling power like crowsor parrots, or primates. They can control their urges and can feel rewards gratification. The experiment was designed around food-reward, and those with most patience would get the better rewards. The study, published in the Royal Society Proceedings,was led by Dr Alexandra Schnell from University of Cambridge's Department of Psychology.
Her team put the cuttlefish to what is known as a “marshmallow test.” In this test, the participant can either get some food straightaway or they can hold out for a more appealing option, like a marshmallow, later on. In case of the cuttlefish, their options were a piece of king shrimp or a live grass shrimp (being the more appealing option).
The cuttlefish could choose an immediate scrap but if they chose live shrimp, it would be provided after a delay. They discovered the most impatient of the lot waited 50 seconds before the live grass shrimp was released to them. Whereas, the ones with more evolved self-control could wait for more than two minutes. Schnell said such behaviour is comparable to animals with larger brains.Professor Nicola Clayton of Cambridge University, co-author of the study, called this behaviour “quite sophisticated.”
This is the first-ever marshmallow test performed on a non-primate, according to Schnell. Cuttlefish has always been an object of fascination among biologists because of their colour-changing capabilities. But with this new research, even behavioural experts and psychologists might take an interest in the species.
In this same experiment, they also explored learning capabilities of the fish. First, they put a black marker and grey marker — one associated with reward. After a few turns, they switched the colours and observed the fish soon developed a new understanding of which colour meant a reward.