Number sense is a pretty big deal for humanity,
underlying the mathematics that empowers our
world -- but now a new study reveals the number
sense of the ever-fascinating cuttlefish.
Cuttlefish are science headline superstars,
so you've probably read about their amazing
chromatic communication systems, shapeshifting
prowess and hypnotic powers.
Of course all of these biological gifts are
useless without brains to power them -- which
is why cuttlefish boast one of the largest
brain-to-body size ratios of any invertebrate.
These amazing little creatures have to be
able to react quickly, learn and adapt if
they wish to score that next meal or secure
themselves a mate.
That's where our latest study comes in, pondering
just how much number sense they employ in
deciding which prey to pursue.
Number sense is essentially how the brain
naturally extracts numbers from the surrounding
environment, similar to how it identifies
colors.
It's not math or a number system, but rather
the primal thing beneath those systems.
To test the number sense of cuttlefish, researchers
at Taiwan’s National Tsing Hua
University introduced a cuttlefish into a
tank, along with a transparent two-chambered
box, so that the cuttlefish might choose between
the two encapsulated meals.
In order to access number sense, they played
with varying ratios between the two boxes.
One shrimp in box A, five shrimp in box B
-- and just about every possible
variation on that.
1 to 4, 2 to 3, 4 to 5.
They even played around with larger shrimp
and dead shrimp to see how those conditions
factored into their decision-making.
They tested 54 different pharaoh cuttlefish
and found that the creatures had no problem
picking larger quantities of shrimp over smaller
quantities.
This entails logarithmic counting, or counting
based on integral increases in physical quantity.
A human infant uses this when picking five
teddy bears over one teddy bear, but the one-month-old
cephalopods beat that by excelling when the
rations grew harder to discern, such as five
shrimp to four shrimp, a feat that larval
humans tend to fail at.
In fact, the researchers theorize that given
the longer computation time in these incidents,
the cuttlefish are not only using logarithmic
counting, but are actively engaged in counting
the shrimp zipping about in each box.
The cuttlefish factored in additional preferences
-- live shrimp are better than dead shrimp,
bigger shrimp are great, but are riskier -- but
the creatures can at least count to five and
maybe higher, even if their unlanguaged minds
lack words for the quantities.
We can scarcely fathom the mind of the cuttlefish
-- just try to imagine number comprehension
without knowledge of the names and symbols
we use.
Their intelligence is alien to us, yet quite
comparable in number sense to human infants
and other primates.
So think about that the next time you see
a cuttlefish at the aquarium, perhaps counting
the number of hairless apes crowding up to
the glass.
What's your take on this?
Let us know, and if you crave more weird science
wonder, be sure to visit
now.howstuffworks.com each and every day.
