Essentially, it was designed to test the willpower of children, aged between 3-5.
And the children were offered one marshmallow and they were able to eat the marshmallow,
but they were also told that if they could wait up to 15 minutes,
without eating the marshmallow, they would receive a second marshmallow.
And then later studies found that this ability is also linked to general intelligence.
Now, this Marshmallow test has since been adapted and tested in different animals, including, you know,
chimpanzees, crows, parrots, dogs, rodents, but it has never been before, it's never been adapted
to test for self-control in an invertebrate. And so that's what we set out to do.
We wanted to test whether cuttlefish had the capacity to exert self-control.
So we wanted to test them, but, obviously, they don't like eating marshmallows.
So we had to change what was on the menu. And we tested them using different types of shrimp.
I'm Alex Schnell. I'm a postdoctoral researcher at the University of Cambridge
in the Department of Psychology. I have a background in marine biology
and animal behavior. But now I am a comparative psychologist.
So I compare the cognitive abilities of different animals. And the particular animal that I'm really
interested in are cephalopods, which are large-brained mollusks, and they include
the octopus, cuttlefish, and squid.
What we were most surprised about is the amount of time that the cuttlefish could wait.
So, the level of self-control shown by the cuttlefish were comparable to what we see in more large-brain
vertebrates, because there is evidence of self-control in the range of diverse animal species.
But the tolerance to temptation varies across taxa. So, animals, such as chickens, rodents, or pigeons,
they can exert self-control, but it's only for several seconds. Whereas animals, such as
chimpanzees, crows, and parrots, they show more advanced self-control, and can wait up to several
minutes for food of better quality or quantity. And so, the cuttlefish in our study showed comparable levels of
self-control to this latter group, waiting up to 50 to 130 seconds
for their preferred food, which was pretty astounding.
By being able to determine, you know, the cognitive similarities or differences amongst very diverse taxa,
it can help locate the origins of intelligence and give us a more
comprehensive understanding of the evolution of intelligence.
Even though the cephalopod brain is shaped so differently to the vertebrate brain,
it actually shows more similarities with the vertebrate brain than its snail relatives.
So the structures are completely different, but they've shown to be analogous.
One particular example is the hippocampal formation, which is involved in learning and memory
in mammals and birds, is analogous to the vertical lobe in the cephalopod brain. And that's pretty
interesting because it updates our understanding of the evolution of intelligence
and why and how certain capacities evolved.
So cuttlefish, squid, and octopus have a beak, like a parrot. And the brain is wrapped around that,
essentially. So it's very different from the vertebrate brain, which the vertebrate brain is made up of five
lobes and it has very distinct hemispheres – left and right hemisphere. Whereas the cephalopod brain is
donut-shaped, made up of 30 to 40 lobes, depending on if you're talking about an octopus or a cuttlefish.
And they have really different structures. But it's just incredible that we've still found functional similarities
amongst these structures that can appear to support similar cognitive features, such as self-control.
I wish that more focus would be put on marine life.
The cephalopod brain is so different from the brains that
are more commonly studied, so, if you're interested in alien-like intelligence, this is it.
This is as close as we're gonna get, and it's right here in our oceans.