Can you imagine having taste buds on your feet? Octopusses depend on taste buds in their suction cups to determine whether foreign objects are edible. Science Friday takes us “Inside the Lab” with Frank Grasso of Brooklyn College to share some insights about these curious creatures.
Living like an octopus
Can you imagine having taste buds on your feet?
Octopuses depend on taste buds in their suction cups to determine whether foreign objects are edible.
Up next, Science Friday takes us inside the lab with Frank Grasso of Brooklyn College to share some insights about these curious creatures.
How does an individual organism experience the world?
Maybe I can never really know what it means to be an octopus, but I am a firm believer in the idea that, if I think well enough, I use my imagination, and I'm critical enough about the evidence, that I can arrive at a reasonable approximation.
♪♪ I'm Frank W. Grasso, and I am a professor of psychology at Brooklyn College, at the City University of New York.
is a wonderful, wonderful concept that I'm very fond of, and it's a German word that means like 'the world around us.'
Octopus, their senses are dominated by vision and by touch and by taste, and they have a little bit of chemical sense.
How those atoms of sensation are organized into perceptions in the animal is the A large part of their nervous system is devoted to manipulating objects under the guidance of their touch-taste system.
And by the way, the octopus arm has roughly 300 suckers apiece.
Each one of those has on the order of 10,000 sensory neurons.
There are mechanical sensors.
So they could actually not only discriminate textures but shapes with their suckers.
Their chemical sensors, they provide a sense of taste.
Imagine walking across a floor with bare feet, and you're tasting the surfaces as you walk along.
Psychologically, for humans, that's kind of repugnant, but, for an octopus, I think that's probably what gets their juices flowing, so to speak.
There is a lot of 'intelligence' in the arm.
What we found with our collaborators at Hebrew University in Jerusalem -- there is this kind of reflex that the sucker produces when it makes contact, sort of like, 'Suck first, ask questions later.'
And then that gives it time to be able to form a chemical impression of whether or not this is a thing to be rejected or accepted.
Fish it would attach to.
Food items and so forth -- it makes good sense to attach very, very quickly to a food item so it doesn't get away.
Neutral surfaces it would attach to.
A fast-flowing current or tidal situation -- you want to attach so you're not carried away.
Other octopuses it would attach to with a slightly lower affinity.
But it would not reflexively attach to its own tissue.
There must be a specialized set of receptors for self-recognition in the rim of the suckers.
The octopus needs to have that kind of recognition because the risk of self-entanglement is an important one.
I don't know that the octopus' brain has access to that information of self.
It could be a completely local sense, that this reflex is simply suppressed.
The other part, I would say, is the visual part.
They really only have one visual pigment.
So, we have three -- red, green, and blue.
Octopus won't be able to see those.
They be able to sense the same wavelengths as we are, but they wouldn't organize them in the same way.
But the octopus can in fact tell what orientation the light is in.
They can see planes of polarized light, so their perception of the world would be fundamentally different from ours.
And the amazing thing about this is that they are still able to generate color patterns on their body that are a good match to the background.
And, really, nobody knows how their brain's doing this.
It's one of these amazing tricks that we need to figure out.
In the ancient theories of neuroscience, there's this idea called the homunculus -- the little man inside the head that's viewing a screen of all the sensory information and is pushing the buttons.
In the case of an octopus, the brain of an octopus resides just behind the eyes.
It is a very elaborate structure that moves around the octopus' esophagus.
Whenever the animal swallows something, the brain's gonna get stretched to allow that item of food to pass through the esophagus, so who knows what's happening in terms of a sensation inside of the brain?
Pardon the pun, but I can't resist -- it does take a 'stretch' of the imagination.
But then three fifths of its brain is located in the animal's arms and a complex network of cells which interconnects the arms.
So, who's in control?
The octopus is in control of its body.
Whether or not it's the brain behind the eyes or the brain inside of the arms or a union, a sort of republic of reflexes between the two of them, that's an open scientific question.
There are oceans of things still to be learned, and while we have these islands in the oceans of certainty that are rock-solid from really good research, the whole picture isn't even an outline yet.
They truly are the closest thing we have to aliens on this planet in terms of the way their brains are organized and work.