You’ve probably heard of a little thing called the scientific method, right? Well, it might be hard to come up with an experiment to test this out, but here’s a hypothesis that strikes us as pretty spot-on nevertheless:
Science never ceases to be fascinating.
Here’s our evidence:
In January, a group of scientists at the University of Minnesota published a study in the journal Science Advances. In it, they describe how—I kid you not!—they slapped some 3D glasses on eleven adult cuttlefish, plopped them down in front of a television, and showed them a movie starring some shrimp.
Why? To learn more about how a tiny marine animal that doesn’t even have a backbone evolved to have eerily human-like eyes.
(By the way, if you don’t want to trudge through the very complex academic paper linked above, you can also read this news article about the study. If you do make it through the complex academic paper, please help us understand the equation N = ∫(1 − exp( − kS(λ)l)) × R(λ)d(λ). It shows up about halfway through.)
This story about cuttlefish got us thinking about a few things. With these adorable, movie-watching invertebrates as our tour guides, we humbly invite you to join us on a trip down an internet rabbit hole of curiosity:
Rabbit Hole Stop #1
First things first: what are cuttlefish? They, like the squid and the octopus, are a type of mollusk called a cephalopod. They are good hunters—shrimp is a favorite dish of theirs, in fact—and they have remarkable camouflage abilities.
Second things second: what makes a cuttlefish’s vision so similar to that of humans? Both cuttlefish and humans have stereopsis. That means they can perceive depth, and they do so using two eyes, which we call binocular vision.
While humans and cuttlefish have similar eyes, though, the way their brains process what those eyes take in is likely different. As the researchers say in their paper, “Further investigation is required to uncover the neural mechanisms underlying the computation of stereopsis in these animals.” Translation: it was hard enough getting these cuttlefish to wear 3D glasses and watch a movie about shrimp, so it might be a while before we get around to figuring out how their brains work, too!
Rabbit Hole Stop #2
If it took until 2020 for us to determine once and for all that cuttlefish have stereoscopic vision [insert joke here about 20/20 vision], when did we figure out that humans have stereoscopic vision?
Answer: 1838. That’s when an English physicist named Charles Wheatstone first explained the concept in a paper called “Contributions to the Physiology of Vision.—Part the First. On some remarkable, and hitherto unobserved, Phenomena of Binocular Vision.” Catchy title, I know!
Wheatstone proposed that “the mind perceives an object of three dimensions by means of the two dissimilar pictures projected by it on the two retinæ.” He also wondered the following: “What would be the visual effect of simultaneously presenting to each eye, instead of the object itself, its projection on a plane surface as it appears to the eye?” He invented a device called the stereoscope to accomplish just that. It’s not such a stretch to say that Wheatstone came up with the idea of 3D movies right then and there.
Rabbit Hole Stop #3
Let’s go back to cuttlefish for a moment.
Just as cuttlefish are really good at hunting shrimp, humans might want to think about getting better at hunting cuttlefish. According to this article, cuttlefish could become a very important food source as the world’s population continues to grow. It’s not such a crazy idea. After all, humans have been eating cephalopods for thousands of years.
“Garçon, more cephalopods, s’il vous plait!”
Rabbit Hole Stop #4
Okay, back to stereoscopic vision. When we left off, it was 1838 and Charles Wheatstone had shown us that humans have binocular vision and can perceive depth.
It took Wheatstone until 1852 to deliver “Part the Second” of his paper on stereoscopic vision. In the meantime, something very important had happened: photography had been popularized. It turns out that stereography and photography were a match made in binocular heaven.
Soon after, Oliver Wendell Holmes and David Brewster set off making stereoscopes the must-have entertainment device of the mid-nineteenth century! Civil War stereography was a big deal, for instance.
Rabbit Hole Stop #5
Stereoscopic vision isn’t just for cuttlefish and nineteenth-century thrill-seekers! In fact, it has become otherworldly. As a follow-up to Curiosity, NASA plans on sending a new rover to Mars in 2020. And yes, it’ll be equipped with stereos cameras—essentially two eyeballs that will be able to take 2-megapixel photos and help the rover navigate the surface of Mars in color and in 3D.
Rabbit Hole Stop #6
While NASA is busy preparing to go back to Mars, let’s close our own journey down the rabbit hole with this, an interactive trip to the deepest depths of the Earth’s oceans. I don’t think we’ll see any cuttlefish, but we will come across something called a cookiecutter shark, as well as some spectacularly named squids—the vampire squid, the firefly squid, the colossal squid, …
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