Cuttlefish pass a test examining intelligence in humans

The cephalopods involved in the experiment passed an intelligence test, which is designed for human children and tests cognitive ability.

The cephalopod was subjected to the so-called Marshmallow test, which was developed in the late 1960s by Walter Mischel and consisted in the ability to forego immediate but small benefits in favour of larger ones, but postponed.

-- Advertisement --

More specifically, the whole experiment involves the child being placed in a room with a candy and being told that if they don’t eat it for 15 minutes, they will get another one and can then eat both. The ability to defer pleasure demonstrates cognitive abilities such as planning for the future.

The whole project was designed primarily to explore how human cognition evolves, and in particular to establish the age at which people are intelligent enough to postpone pleasure if it will allow them to achieve a better outcome.

Of course, you cannot tell an animal that it will get a better reward if it waits, but you can teach it by adjusting the test accordingly. E.g. so that the test creature knows that it will get better food if it does not eat what is now in front of it.

The cuttlefish is another animal after dogs and some primates that can delay gratification, even if it can’t be consistent. Interestingly, some birds in the corvid family also pass the candy test.

The test was designed for six common cephalopods, which were placed in a special tank with two enclosed chambers with transparent doors so the animals could see what was inside. For snacks, the least favourite piece of uncooked king prawn was chosen and placed in one chamber, while the other chamber contained a live variable prawn.

There were symbols on the doors to the chambers so that the cuttlefish would learn to recognise them. A circle meant that the door would open immediately. A triangle, on the other hand, that the door would open between 10 and 130 seconds. The experiment is an interesting example of how different species with completely different lifestyles can have similar behaviour and cognitive abilities.

Scientists plan to subject the cephalopods to further tests to try and see if the cuttlefish are indeed able to plan their future actions.

Photo Hans Hillewaert/wikipedia.org CC BY-SA 4.0