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FRANK W. GRASSO: 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.
Umwelt 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 umwelt.
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.
They are 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, quote, unquote,
"intelligence" in the arm.
And what we found with our collaborators
at Hebrew University in Jerusalem,
there is this kind of reflex that the sucker produces when
it makes mechanical 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.
A 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 if the octopus's 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.
An octopus won't be able to see those.
They would be able to sense the same wavelengths as we are,
but they wouldn't organize them 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 is 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 the octopus
resides just behind the eyes.
It is a very elaborate structure that moves
around the octopus's esophagus.
Whenever the animal swallows something,
the brain is going to 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 3/5 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.
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