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FOOLING THE MIND’S EYE
What Soldiers and Fashion Designers Can Learn from the Cuttlefish
An air-shredding volley of bullets headed straight toward your soft, woefully underarmored body can have a powerful clarifying effect on your most recent life choices. What’s happening? Where are they shooting from? How can I hide?
Once might be bad timing, an unlucky brush with death. But when the bullets keep coming, on different days and in different places, the question changes: Why does this keep happening? You start to look a little further back for answers. Bad luck starts to look more like a bad pattern.
A bad pattern was exactly what kept getting soldiers in the U.S. Army nearly killed, according to Major Kevin “Kit” Parker. Parker is a professor of bioengineering and applied physics at Harvard University, but two decades ago he was just a Southern boy who’d decided to join the army partway through graduate school, completing basic training in 1992 and getting commissioned as an officer in 1994.
“Military service is a little bit more common in my family or in the neck of the woods where I’m from—so, you know, if you watch NASCAR and you’re very susceptible to good advertising, you might find yourself in the army,” Parker says, with a laugh.
After joining the Army Reserves, Parker ended up serving two tours of duty in Afghanistan, from 2002 to 2003 and in 2009, and twice in 2011 as part of a special science advisory mission called the gray team. The 2009 tour was particularly rough, a seven-month stretch when Parker’s unit just couldn’t seem to duck the militants. Wherever they went, their convoys kept getting pinned down by gunfire.
“It was a very rough combat tour; I was getting shot at quite a bit,” Parker said. “One day I was out with some Afghan national police and we were on this kind of desert plain that was on the other side of a mountain. There was no vegetation, nothing—and I’m looking at my shirt, this … bluish-green pixelated pattern, and I’m looking at the dirt around me and I thought, ‘I stick out like a sore thumb here!’”
The problem was the camouflage on their uniforms. Known as Universal Camouflage Pattern, or UCP, it was rolled out in 2004 to the tune of $5 billion after several years of development. Blue, green, and pixelated, the design was meant to be an all-terrain garment that would eliminate the need for multiple uniforms. But instead of letting them blend in to all environments, this one-shade-fits-all suit made the army major and his fellow soldiers stand out against what was often a barren, rocky landscape.
“This was a budget-driven decision, rather than a science-driven decision,” Parker said.
There was a combat cameraman on the day that Parker looked around his blue-suited body and had his horrible realization. The cameraman took a photo of Parker down on one knee—an image that would serve as inspiration when he arrived back home.
“All I had to do was kind of look back at my photographs from the war and I see that picture of me out on one knee out in the desert,” Parker said. “It’s like slightly less conspicuous than if I’d been holding a big sign over my head in Pashtun that said, ‘Shoot me.’”
Parker wasn’t the only one with this problem. The camouflage was making soldiers in Afghanistan easy targets—and in 2009 the issue finally reached the ears of now-deceased U.S. Rep. John Murtha (D, Pennsylvania), who reportedly heard from noncommissioned officer Rangers while on a visit to Fort Benning, Georgia. Study after study began to come out showing that UCP was a sub-par camouflage. One report in particular, conducted by U.S. Army Natick Soldier Research, Development and Engineering Center, showed that four other camouflage patterns performed 16 percent to 36 percent better than UCP across the test’s woodland, desert, and urban settings. At least one of those, known as MultiCam, had been available since 2002—which means a $5 billion expense on the research and development of these uniforms could have been avoided.
According to news reports, the issue wasn’t just the colors, or the pixelation (a technique used by several more successful camouflage patterns). The problem was also the pattern’s scale. It was too small, and suffered from a phenomenon known as “isoluminance,” where a pattern’s colors are so close together that they blend when seen from a distance and make the entire form stand out. In the case of UCP’s light-toned colors, the soldiers’ outlines became light-colored silhouettes, making them easy to see against the background. In other words, it could be making the soldiers more visible and thus, less safe.
In the wake of public and insider outcry over UCP, MultiCam was adopted as a temporary fill-in pattern for Afghanistan; a new pattern similar to MultiCam was reportedly debuted in 2015. But when it comes to developing new, effective military camouflage, Parker said, “We still aren’t getting it right.”
* * *
There has to be a smarter way to approach camouflage than coming up with a one-size-fits-all pattern, Parker thought. The problem hung in the back of his mind after he returned from his second tour of duty. And then, in the fall of 2009, some two months after returning home, Parker got a call from Evelyn Hu, an optical physicist at Harvard, inviting him to work on a project funded by the Defense Advanced Research Projects Agency—DARPA, that defense department outfit that midwifed the Internet in the 1960s and 1970s and still funds cutting-edge, futuristic research today. Hu’s project, however, was at least fifty million years old: the cuttlefish, an alien-looking sea creature that—at least in the United States—is less well-known than its close relatives the octopus and the squid.
While the cuttlefish may not be as recognized as its eight-armed cousins, it rivals them in a number of aspects, including its intelligence and its incredible shape-shifting, shade-shifting skin. The animal can change its coloration in about 300 milliseconds. Hu wanted to partner up with a marine biologist named Roger Hanlon, a researcher at the Marine Biological Laboratory (MBL)in Woods Hole, Massachusetts, and a leading expert in cephalopod behavior (the group that includes cuttlefish, squid, octopuses, and nautiluses). And Parker realized that Hanlon’s office just happened to be nearby.
“I said, you know what? I’m right here. I’m going to walk over there and get this guy,” Parker said. The three scientists teamed up with several other colleagues and went on to publish a 2014 paper on the nanoscale color-changing mechanisms within cuttlefish skin.
Parker happened to be visiting the Marine Biological Laboratory’s library when he got Hu’s call—a library near whose doorway hangs the somewhat ironic inscription, STUDY NATURE, NOT BOOKS. It was said by Louis Agassiz, a groundbreaking biologist who helped inspire the creation of the MBL. It’s one of Hanlon’s favorite quotes. He cites it often, in joking defense of his research habits.
“Certainly that’s my excuse to get out in the world and go diving a lot,” Hanlon says.
That’s something of an understatement. Over his roughly thirty-five-year career, the biologist has performed around five thousand scuba dives, everywhere from Australia to South Africa and the Caribbean. (Among his favorite spots: Palau Islands of Micronesia and Little Cayman Island.) But back in the lab, he has a whole slew of captive cuttlefish whose stealth and smarts he and his colleagues can study on a daily basis.
I’m sitting in his office in Woods Hole, Massachusetts, at the Marine Biological Laboratory, one of the research stations hanging along the cape, just down the street from the dock that takes summer vacationers to the island known as Martha’s Vineyard. It’s a cold, clear, and quiet day in December, and the light has a thin, golden touch as it hits the enclosed harbor known as Eel Pond. Hanlon’s office looks out onto the water, a tiger-striped Nautilus pompilius shell on the windowsill punctuating the view. Books on his shelves have a certain theme: Vision and Art: The Biology of Seeing; Neurotechnology; Butterflies; and a beast of a book with the no-nonsense title, Disruptive Pattern Material stamped across its double-wide spine.
“An interesting book,” Hanlon notes, when I point it out. “That guy made a fortune off of clothing.”
Hanlon is a sort of Renaissance man of marine camouflage, but for the most part he studies all manner of cephalopods—various species of squid, octopus, and cuttlefish. When I ask him which his favorite is, he laughs, almost surprised. “The European cuttlefish is pretty phenomenal,” he says. “The one we have in our lab here. I’ve worked a lot on them; it’s a really neat animal.”
In the United States, the cuttlefish has long been the lesser-known cousin of the octopus. They inhabit the coasts off of Europe, Asia, Australia, and Africa, but somehow seem to skirt the Americas. Like their squid cousins, they have eight arms and two tentacles. Aristotle admired their iridescent innards; during his time, the animals were prized for their ink, which they spew out just as the octopus and squid do in order to throw up a defensive curtain and escape. They’ve long been called the “chameleons of the sea,” for their ability to blend in to their surroundings.
“These animals also escape detection by a very extraordinary, chameleonlike power of changing their colour,” Charles Darwin wrote in his seminal 1860 book The Voyage of the Beagle.
You may not be able to think of a weirder, more otherworldly creature than the cuttlefish. It has no backbone, strange W-shaped pupils in its bulbous eyes and thick floppy-looking arms protruding from its face. It swims around with a tutu-like frill that floats around its body, but propels itself backward to escape predators. To look at its many-fingered face is to look into the visage of Cthulhu, that fictional god of H. P. Lovecraft’s strange horror stories, or the alien Ood of the rebooted cult TV show Doctor Who.
If you think there’s little similarity between a human and a tuna fish, consider this: at least they both have backbones. As a member of the cephalopods, the cuttlefish is from an even more distant branch of the family tree than true fishes. Cephalopods, an extremely mobile group of animals that includes fellow shade-shifters like the octopus and the squid, are thought to be the brainiest group of invertebrates on the planet.
The modern cephalopod lineage first emerged more than five hundred million years ago, before even sharks had come to be. They arose from animals known as mollusks—a group whose living members include the humble snail and the clam, which is essentially a muscle armored with a shell.
How did the very clever cuttlefish evolve from an extended family that even today includes such, well, brainless creatures? The answer may lie in the shell—or the lack thereof, as it were. Mollusks were defined by their protective, calcium-rich armor—the word “mollusk” comes from the Latin molluscus, meaning “thin-shelled.” But while a shell can act as highly effective defense for vulnerable flesh, it can also be a burden—and at some point in their evolution, cephalopods abandoned their external shells, becoming highly mobile hunters and foragers in the ocean. Unlike the squid and the octopus, the cuttlefish does have a flat and oval internal shell called a cuttlebone, which is full of layered chambers. The front chambers are filled with gas and the rear chambers are filled with seawater; and by adjusting the ratio of gas to liquid, the cuttlefish can change the density of the cuttlebone—and thus, its floatability—as it swims around at different depths. That’s a big energy saver if you’re trying to move around and stay afloat. (Cuttlefish also save energy by living a quiet life, often lying on the seafloor and using their arms to toss sand over their bodies so that they’re hidden from sight.)
The trade-off to not having a shell is that you become a very tempting target for every other predator in the ocean. You’re basically a fluid bag of meat. A prepackaged, protein-filled snack. In short: you are pretty easy pickings.
Octopuses and squid, cephalopods who have also shed their shells, suffer from the same vulnerability. So these fleshy creatures have evolved an ingenious system of defense: if you can’t protect yourself when attacked, don’t draw any unwanted attention in the first place. Swim under the proverbial radar. And so they’ve developed this highly specialized camouflage that seems able, at first glance, to match nearly any color under the sea, if not the sun. It’s not a totally unique ability—animals like chameleons can also change color, depending on their mood. But few can do it with the sophistication of the cephalopods, which can not only change color but change intricate patterns that allow them to quickly blend into their surroundings, whether it’s the sandy seafloor or a bundle of wavy kelp. They can even modify the texture of their skin to match their environment, whether it’s rough sand or a sharp-edged reef.
I get a firsthand view of this when Hanlon takes me down the hall to the lab, where the cuttlefish reside. His colleague Kendra Buresch is there in a room that sounds like an Escher sketch of running faucets—tanks full of floating cuttlefish line the far wall, and water circulates through at a high rate, as it would in an ocean environment. The animals are smaller than I expected—roughly the size of my hand—but just as cute as I thought they’d be. (It doesn’t hurt that, to my ear, “cuttlefish” sounds like “cuddlefish.”)
These guys aren’t interested in cuddling, though. As Buresch comes close, one of the animals lifts two of its arms up in the air—almost as if begging for food (though I’m told later by Hanlon that it’s a startle or threat response). They definitely have personalities, Buresch said, as she held a finger over the water. The cuttlefish focuses on her finger, and two dark, slightly wavy lines grow and thicken across the length of his back; they remind me of the twin flowing f-holes carved into a violin. The longer the cuttlefish stares at Buresch’s wiggling finger, the thicker those markings get—as if someone’s trying to fill in a narrow line with a blunt, wet sharpie, and the color is beginning to bleed outside the lines.
“So now he has a pattern on, that’s frequently the pattern they get when they’re hunting,” Buresch says. “I just don’t want him to grab me—it’s fine, I just don’t like the way it FEELS!”
Buresch’s voice rockets up two octaves at that final word, as the cuttlefish, who can stand it no more, lashes out with its two feeding tentacles and latches onto her finger. Buresch pulls back quickly and the cuttlefish releases its suckered grip, the dark lines on its back fading from front to back and quickly flickering away.
I totally want to try now. The once-fooled cuttlefish won’t be tricked again. Buresch waves her finger in front of him to make sure and he thinks about it—the lines start to draw themselves up his back, but just as quickly vanish. (They’re not in synchrony, so the effect looks somewhat like an alternating eyebrow-waggle, Stephen Colbert–style.)
So I wiggle my finger in front of his companion, who seems a little more trigger-happy. The dark lines appear, and the little guy shoots out his tentacles, hidden behind his eight-armed face, soft little suckers wrapping around my finger. It’s weird but not unpleasant, and I’m thinking about how to describe the feeling and kind of entranced by how the tentacles are shortening, making it look like the cuttlefish is reeling itself in toward my hand, and then I notice that Buresch and her colleague, Stephen Senft (who walked in about a minute before this) are making noises of significant alarm.
I pull my finger back and he doesn’t let go; I pull up, out of the water, expecting him to release—but at this point, his tentacles are so short that he just hangs on for dear life, his single-digit meal almost in reach. So I inadvertently lift him into the air. The shock (or perhaps the gravity) is finally too much for him, and he lets go and plops back down into the shallow tank.
The researchers are noticeably relieved and a little shocked. Senft says he’s played with the cuttlefish before, but has never gotten as close to having his finger become a snack as I did.
“They have a sharp little beak in there,” Senft says by way of understatement. (Its cousin, the squid, has a beak that’s measured to be among the hardest, if not the hardest, all-organic material known—which I’ll get into in the next chapter.) Meanwhile, I’m feeling pretty bad about messing with this poor cuttlefish. I ask the scientists if I traumatized the little guy.
“He’ll be okay,” Buresch says.
Animals that rely on camouflage often make use of pigment molecules that absorb most wavelengths of light and reflect only a tiny slice of the visible spectrum. This works well for most animals with yellows and reds and brown/blacks in their coats (particularly mammals, whose pigments are limited by what their hair can produce). The iridescent shades and blue greens like those you’ll see in the blazing sapphire of a peacock feather are thanks to structural color—building a nanoscale surface that does not absorb light but reflects incoming wavelengths into the blue-green range.
Some animals, like chameleons, can actively change colors at will. Those that can’t alter their appearance on command instead feature large-scale patterns—alarming false eyespots, eye-fooling tiger stripes—that, while static, are remarkably good at disrupting the eye and keeping the wearer out of harm’s way.
The cuttlefish takes advantage of all of these colors and tactics. It can produce red, yellow, and brown; it can create bluey greens and even whites—but it also deploys them the way that permanently camouflaged animals do, using clever patterns to fool the brains of both predator and prey.
I see one of these patterns in action as Buresch turns toward a blue tarp tent—an ice-fishing hut, as it turns out—and unzips it. Inside is a kiddie pool–sized clear plastic tank, in which, inside a large pizza-sized black tub, a pocket-sized cuttlefish sits next to a little checkerboard-covered pillbox. Above the pool-in-a-pool, a camera stares directly onto the spot where the cuttlefish sits.
As Buresch slowly reaches in to grab the black-and-white box—painstakingly slowly, so as not to alarm the cuttlefish—the little animal’s pattern starts to change. A dark spot flares up onto the left side of its back—the side closest to Buresch’s approaching hand—and another one begins to emerge on the right. They’re similar to the dramatic “eyespots” you’ll see on butterfly wings and the backs of fish, meant to startle or confuse an oncoming predator into thinking it’s looking into the face of a different animal.
“He’s trying to fool me and make himself look scary,” she says.
Buresch retreats, checkered tchotchke in hand, and the slightly cockeyed spots fade entirely away. She zips up the blue tent; she’ll be able to monitor him on the video screen placed next to the fishing hut. She’s waiting to see if the cuttlefish changes patterns, now that a key visual cue—the checkerboard cylinder—has been removed, and all that remains is sandy substrate.
A cuttlefish’s environment is visually cluttered, Hanlon had pointed out: sharp rocks, floating algae, branching coral, arm-waving sea anemones, speedy schools of fish, crawling crabs—in the water, there’s a mind-boggling diversity of shape and movement. It’s an overwhelming amount of information to take in, and there’s no way to match it all. It’s like a visual “cocktail party effect”: Imagine yourself at some social soiree, trying to listen to all of the conversations around you at the same time. You’d go mad. Instead, you just try to pick out the most relevant conversation you hear and hold onto that thread, ignoring the cacophony around you.
Cuttlefish do that in their cluttered environments. They focus on a particular visual cue and then sync their camouflage with that cue. And the researchers want to figure out which cues they respond to most strongly—which ones the cuttlefish thinks are most important. That’s why, in the blue ice hut, the little checkerboard pillbox had been placed in the sand next to the cuttlefish.
On the lab counter a few feet away are a few large-pizza-sized circles with different patterns on them, which I flip through—one in the same checkerboard pattern and scale as the pillbox, another in plain gray. These artificial “substrates” get slipped onto the floor of the little black tank, so that the scientists can see whether the animals respond to the ground beneath them or the significant objects (like the checkerboard pillbox) jutting out of them.
The laminated, waterproof substrates also come in smaller and larger-scale checkerboards, because the researchers want to see at what scale the cuttlefish decides it’s time to turn on the bright white square it sports in the center of its back. Fanned out a few inches away are three other random-looking pixelated patterns, at different levels of contrast. They remind me a little bit of the “digital camouflage” that’s the center of the army camo controversy.
Buresch also has substrates that look like plain old pictures of sand. As it turns out, the cuttlefish don’t really care about the texture of the surface they’re on; the ground can be flat as a board and they’ll still respond to it. (I find this all the more remarkable, given the incredible texture-producing properties of their skin, but more on that later.)
Cuttlefish don’t just respond to patterns—they’ll try to imitate the objects around them, Buresch said, recalling an ingenious little experiment Hanlon and a few other colleagues performed. The scientists placed a single cuttlefish in a teardrop-shaped tank with a sprig of artificial seaweed placed near the rounded wall. The cuttlefish would swim over to the fake greenery and raise their arms with a jaunty little crook near the ends to mimic the branching algae. This has been reported anecdotally in the wild: divers have spotted both squid and cuttlefish waving their arms in the ocean currents to emulate the undulating algae around them, making it even harder to distinguish the animals from the background.
Cute as this artful interpretation of marine shrubbery may be, there’s a deeper geometric principle behind it. The scientists next ran a stripped-down version of their experiment, placing patterns on the teardrop walls to see how they’d react. In all cases, the floor was a plain gray, but the walls were lined with thick black-and-white stripes. Sometimes the stripes were vertical, sometimes they were horizontal, and sometimes they were diagonal. And the scientists found that the cuttlefish would actually try to follow the direction of these lines with their arms, holding them straight out for the horizontal pattern, straight up for the vertical pattern, and at a slant for the diagonal patterns.
But even though the animals respond to simple, two-dimensional designs, they can turn their skin into exquisite three-dimensional structures to match their surroundings. The cuttlefish, like the octopus, can also make its skin extend these little branches, which can sprout tinier branches until their whole bodies look like a spiny fragment of coral. It’s truly remarkable, Hanlon said, and still something of a mystery. They know it functions as a muscular hydrostat—the way your tongue does, with one end anchored and the other end free-moving—but it’s as if your tongue was able to reform with two branching mini-tongues at the end.
That’s not what Buresch is looking at in her work, however. After switching out the surface pattern beneath the cuttlefish in the ice hut, she’s been giving the animal a little time to settle down before checking to see if he’s adjusted the markings on his body. With no pillbox nearby, Buresch expects that he’s gone from high-contrast to sandy-tone, though she has to check to be sure.
You might think, at this point, that the cuttlefish is such a master of disguise because it’s able to perfectly match its surroundings. In that case, the perfect camouflage would be, essentially, the perfect invisibility cloak; it wouldn’t make its wearer transparent, but would precisely match its surroundings, changing with the scenery. That certainly sounds like a tempting solution for man-made camouflage—it would solve the military’s problems with UCP, enabling soldiers to adapt to tan deserts and lush forests without ever stripping down and suiting back up. But think about that idea for a moment, and it quickly starts to fall apart. First, it would require an enormous computer to process the visual environment and spit it out onto the clothing, which would be expensive to build and impractical to carry; and it would really only work if you move slowly or stand still. After all, if you’re in front of a tree and then step a few inches to one side, unless your clothing works instantaneously and from all angles, you may suddenly look like a glaring brown target to a sniper scanning for your mostly defenseless body.
No two environments are exactly alike—and in fact, no single environment is exactly like itself, when viewed from different vantage points. Lucky for the cuttlefish, camouflage is never really just about looking like your surroundings (though it helps). Consider a tiger’s stripes. The black stripes don’t just help the animal blend in with the shadows; they also serve to break up the tiger’s silhouette, because animals, humans included, are primed to look for full-body outlines. That’s why a tiger’s stripes suddenly cut off near the ankle—they make it harder to quickly identify.
The cuttlefish has to fool a range of predators (large fish, diving birds, sharks, and seals) and prey (fish, crabs, mollusks—a variety of small and tasty creatures). They can see at night; some can see ultraviolet wavelengths of light. Luckily for the biologists who want to understand it and the engineers who want to mimic it, the cuttlefish is not actually trying to match its environment to a T. In fact, Hanlon says, its true power comes not from its ability to fool the eye, but its talent for fooling the brain.
* * *
Here’s what Hanlon started to notice, after observing countless cephalopods, cuttlefish included, react to their surroundings: In spite of the incredible detail the animals put into their disguises, each one was not unique. In fact, the vast array of camouflage patterns all seemed to boil down to three (maybe four) basic templates. So in the thousands upon thousands of slightly different situations a cuttlefish might find itself in its one-to-two-year life span, it only ever uses three different disguises. How’s that for universal camouflage patterns?
That may sound pretty bonkers at first, though it starts to make a little more sense when you know what the patterns are. The first is a uniform/stipple pattern; it’s low-contrast and meant to blend in with a nice, even sandy bottom. The second is a mottled template; it’s higher contrast and more uneven (think light-and-dark marble-sized pebbles). The third is what the researchers call “disruptive”: a very high-contrast and very large-scale pattern, a big, boxy, bold design whose main feature is a giant white square on the cuttlefish’s back. This pattern is used when there’s a high contrast environment (preferably with large white rocks) where there’s no way the cuttlefish can really blend all the edges of its body to its surroundings. Instead, in a more dramatic (and perhaps effective) way than the tiger stripes, the cuttlefish makes faux edges inside its own body—which dramatically break up the cuttlefish’s actual silhouette, making it very difficult, visually, for predator or prey to piece its body outline together.
If you don’t believe that the brain can be so easily fooled, consider the Rubin vase. You’ve seen it before: that black-and-white image that either looks like a white chalice, or like the silhouetted profiles of two men facing each other. Both are part of the image that your eyes see, but your brain has to decide if the edge between black and white belongs to the vase, or to the men. Stare at it for several moments, and you’ll feel your brain switching between the two. Vase! No, men! No, vase! And so on, until you get a headache like I just did while testing it out. The brain has to decide which line to follow—and it has a very hard time holding both images in mind at the same time. The cuttlefish’s disruptive pattern, while its dramatic coloring might seem to attract attention, takes advantage of our brain’s search for outlines. It creates false borders, forcing the brain to divvy up an object incorrectly, and thus miss the profiles of the animal entirely.
In an ideal world, that’s exactly what smart man-made camouflage is meant to do—and what UCP was supposed to do (and did not, according to Natick-led reports in 2009 and 2010). To me, it seems the pattern didn’t take into account lessons learned by many different animals, including the cuttlefish. For the cuttlefish, scale plays a key role: The pattern has to be big enough, the pieces of the puzzle large enough, that the brain doesn’t see the whole for the parts. This was part of the issue with the army camouflage: the pattern was too small-scale to break up the soldiers’ silhouettes. Personally, I’m starting to think that if they’d studied the cuttlefish, they might have realized that was not the best idea.
Regardless of any military experts’ interest in the topic, scientists continue to study natural adaptive camouflage simply for the sake of getting the basic science down. For example, Hanlon and his colleagues are still trying to clearly demonstrate that there are only three (or four) patterns—and that takes a ton of work, he said. You have to gather thousands upon thousands of images, develop an algorithm to analyze them, and see if they all fit the pattern or if there are any outliers. It’s a huge, data-driven effort, and it’s difficult to prove.
But they’re hacking away at the data, because it is a stunning idea. It means that, no matter the type of animal, from mammals to fish and birds, all visual predators have brains that operate by the same fundamental rules—and they can all be tricked in some basic ways. That is an idea that’s not just of interest to military experts, but to any and all biologists looking to understand the behavior of different species, the environmental factors that shape their evolution, and the common cognitive structures they share.
But the researchers have to do more than simply prove that these underlying pattern templates exist. They want to understand when a cuttlefish decides to use one or the other. After all, a cuttlefish’s environment can be overwhelmingly complex; it might include a nice patch of smooth sand, some mottled coral, or a bunch of large rocks where putting on a disruptive pattern would work nicely. Which one does it choose? Understanding this big-brained animal’s decision-making process will shed light on what the camouflage priorities should be in a given environment.
For example, cuttlefish seem to prefer coordinating with three-dimensional objects in their environment. Put them on a sandy substrate with a light-colored rock off to the side, and they’ll swim straight over to the rock and light up the white box on their back—even though they could just as well put on their sand-tone uniform pattern and hang out anywhere else in the tank.
Of course, if the rock were also sandy-looking, then they would pop on the uniform pattern; if it looked mottled, they’d throw on the mottled pattern. For the cuttlefish, the order of priority seems to be matching with three-dimensional objects, then two-dimensional vertical patterns (such as seaweed in the wild or the walls of the tank in Hanlon’s experiments), and finally the two-dimensional patterns of the ground beneath them.
These are the sorts of questions Buresch is exploring with experiments akin to today’s very informal demo—which she went to check on before I left her lab. Before she’d removed the checkerboard pillbox from the pool, the cuttlefish had swum right up to it and donned its disruptive pattern. Now that she had pulled the pillbox out, she expected (as she’d seen many times before) that the disruptive pattern would fade away in favor of a sandy, uniform tone. But when we looked at the monitor, its disruptive pattern seemed even more high-contrast than before.
“They don’t like to cooperate when people are staring,” Buresch says. Somehow, I’m not surprised.
* * *
Understanding why a cuttlefish chooses a particular camouflage is one thing. Understanding exactly how it manages to do this is another problem entirely. It requires a whole different set of tools, because the secret of the cuttlefish’s color-changing powers lies on the scale of individual cells. Once you understand the micro-scale mechanisms that underpin rapid adaptive camouflage, you have a fighting chance to actually replicate it. Then, once you replicate these mechanisms, you can potentially mass-manufacture textiles that harness them. That end goal is what draws people like Kit Parker, who sees the promise from a military standpoint.
Before that can happen—and whether or not that happens—biologists need to understand the tiny organs, called “chromatophores,” that make this system work. That’s up to researchers like Stephen Senft, who’s showing me a baby squid under a microscope. The squid is tiny, about the size of a very small ant; but stuck on a slide, stained in a special dye and placed in the scope, the pigment organs show up clearly as dark polkadots underneath its translucent skin.
Cephalopod skin has proven devilishly difficult to study, and it has taken several decades of painstaking examination and key developments in microscope technology to finally get scientists to a point where it’s even possible to grasp the nanoscale mechanisms at work.
There are half a dozen microscopes in this building, which sits across from the building where Hanlon, Buresch, and Senft work. Before this little field trip, Senft had arrived just in time to see the cuttlefish almost take my finger off and had led me away before I could traumatize any more animals, up the stairs to the lab bench where he does much of his work. Like I said, understanding the skin’s powers requires a different set of tools—mainly different kinds of microscopes: some traditional, some that use lasers, some that harness electrons in order to see structures that are smaller than the wavelength of light. And in his office, he pulls up some of the fruits of that study: strangely beautiful images of balls of different sizes, strung together like a tangled pearl necklace.
Senft is one of the scientists who worked with Parker and Hanlon and Harvard optical physicist Evelyn Hu to try and understand the complex physics of cuttlefish skin. And complex it is, made of several layers, shot through with muscles and nerves to control the colors that appear and fade on the surface, as well as the texture it takes on. And it can do this in a matter of 300 milliseconds. In animals like the chameleon, the brain sends out messages using hormones that float through the bloodstream and eventually change shades over several seconds or minutes. The cuttlefish operates much faster, because it can send messages from the brain via nerve impulses. They’re incredibly long, superhighway nerves, Hanlon said—single strands running straight from the brain to the muscle, rather than being relayed along several nerves at synaptic crossings. These nerves connect to the muscle fibers controlling the chromatic organs in each layer of cuttlefish skin.
The scientists wanted to know what was happening at the receiving end of those neural instructions: how were the cuttlefish creating yellow-brown patterns that masked their bodies, or using neon blue-green hues to show off to females, or generating the blinding white of their eye-fooling square?
Turns out that understanding how cuttlefish skin works is a multilayered operation. In other color-changing animals, chromatophores essentially just contain pigments that act as selective color filters. But, as the scientists found when they put cephalopod skin under a microscope, that’s not the case at all with cuttlefish skin. It’s a far more complex—and ingenious—operation.
There’s a reason the scientists refer to the chromatophores as “organs,” not mere pigment-filled cells, Hanlon said. There are several different cell types involved in the operation of these structures, including muscles and nerves and pigment sacs. The pigments, like the dyes in your clothing, absorb almost all incoming light and reflect back only certain wavelengths. In the case of the cuttlefish, it has chromatophores with either yellow, red-brown or brown-black pigments, each in their own layer: yellows on top of reds on top of browns.
Beneath those three layers of pigmented chromatophores are the iridophores, which operate by a totally different optical trick. These cells take advantage of a protein called reflectin, which has some pretty dazzling properties. Reflectin doesn’t absorb light; it takes incoming light and manipulates it by forcing the waves to bounce off of its surface at different angles. Those crisscrossing light waves interfere with each other, creating what’s known as structural color. It’s the same principle behind the iridescent blues and greens you’ll see inside an abalone shell, or on a butterfly wing, or even on a glistening slab of meat at the butcher shop. Pigments, like the yellow, red, and brown of the chromatophores in the upper skin layers, absorb and reflect the same specific wavelengths at pretty much every angle. But in the iridophores, platelets composed of reflectin shoot the wavelengths out at different angles all over its surface, which is why, if you move an iridescent object from side to side, changing your viewing angle, it seems to shift colors. It’s a beautiful mastery of optical physics—and a dazzling sight to behold.
Cuttlefish have certainly learned how to wield their varied color palette well. While the primary purpose of their color-changing skin may be keeping the animals hidden, out of sight, they have also learned to harness it for hypnotizing their prey. A cuttlefish will put on a show for an unwary crab, running colors across its skin like it’s a Las Vegas marquee. The hapless crab, unable to look away, will just sit there, apparently transfixed. Still flickering, the cuttlefish will inch ever closer until—bam!—its two tentacles shoot out, grab the crab, and pull it toward its mouth. Imminent death never looked so pretty.
And now we’ve reached the final, lowest layer of cuttlefish skin responsible for color: the layer of leucophores. Leucophores have an essential task: they produce the whites in the cuttlefish skin. And while white may seem like a fairly, well, vanilla color compared to the psychedelic, shade-shifting iridophores, it’s one of the most challenging layers to understand—and it’s the layer that Stephen Senft focuses on.
Like the iridophores, the leucophores also carry granules made of that strangely folded protein, reflectin. But in the iridophores, those reflectin proteins are incorporated into little plate-shaped structures; in the leucophores, they’re built into spheres. So instead of producing the shiny, shifting hues that the iridophores do, the leucophores produce one of the whitest whites in both the natural or man-made world. What does whitest white mean? It means whiter than milk. It means whiter than paper. Senft, sitting at a laboratory bench one floor above Hanlon’s office, pulls up a graph showing the spectrum of light of paper and of the cuttlefish leucophore. Keep in mind, white light is made up of all the colors of the visible spectrum, from red to indigo. But the graph showing the paper’s whiteness is full of sharp dips where certain wavelengths—that is, certain colors—are missing. The graph for the leucophores, on the other hand, is essentially flat and even all the way through—few to no dips. It includes nearly all wavelengths equally, and is thus a nearly perfect white.
Senft in particular is interested in understanding how it is the leucophores do what they do. He’s committed to cracking open the black box that these white-producing sacks of protein represent. Among the mysteries: why some of the granules are spherical, and others are flat as plates. Presumably, if you want to create an all-over white, your granules would all be spheres—but that’s clearly not the case. Senft and his colleagues suspect that there’s an optical reason for the plates’ existence, as well as the direction in which they’re aimed and the way they’re spaced out. The cuttlefish can’t manipulate iridophores and leucophores the same way as it does the pigment-filled chromatophores, Senft said—as far as they know, anyway. So their size, shape, and distribution must be perfectly arranged to generate that whiteness. He shows me images of the insides of leucophores that he’s taken, holding both spheres and plates that are a few hundred nanometers across.
“We don’t know what the reason is that one [cell] should have one [shape] and one should have the other, because as far as we can tell, they’re from the same pool of cells,” Senft said. “So we’re interested in trying to follow further what the biochemistry might be that leads to one or the other.”
Now that we understand the basic components of cuttlefish skin, you might be wondering how they all work together. How do the whites and blues and greens ever get seen if they’re covered by the yellow, red, and brown pigmented cells?
These aren’t just sacks of moving pigment, as in the chromatophores of other animals, like color-changing frogs. It’s a complex, self-contained, sophisticated mechanism. In the cuttlefish’s chromatophores, the yellow, red, and brown pigment-filled cells are surrounded by eighteen to thirty muscle fibers (depending on which of the more than a hundred species of cuttlefish you’re talking about). These muscles radiate out like the spokes in a wheel, and the cuttlefish can squeeze those muscles, shortening them and pulling the pigmented cell out from a small point to a wide disk, covering a much larger surface area. Now, instead of being a tiny pinprick of red, barely discernable on the surface, it’s a broad disk, expanded to 500 percent of its original size. If it “opens” all of the red chromatophores, it will look red. If it relaxes the reds, letting them fall back to pinpoints, and tugs on the yellows in its skin, that stripe will suddenly be replaced by sandy yellow tone. It can do this so fast—inside a few hundred milliseconds—that the patterns seem to zoom across the animal’s body. That’s why the dark, inky markings I saw running across Buresch’s finger-hunting cuttlefish could so quickly erase and redraw themselves.
But then how do we ever see the iridophores and leucophores? Basically, those two layers, full of reflectin-filled cells, are always “on,” and they mostly rely on the pigment-filled, muscle-controlled layers above them to block them from view. Some areas, like that disruptive white square in the middle of the cuttlefish’s back, have a higher density of leucophores, which is why they can look so blindingly white.
And if you’re wondering why the iridophores don’t block out the leucophores, well, so do the researchers. Scientists aren’t sure to what extent the iridophore plates’ movements are controlled—all they know is that these particular cells are not neurally directed the way that the pigment-filled chromatophores are. It seems that the movement of the iridophore platelets is controlled by a neurotransmitter—so that changes happen over longer timescales, seconds or minutes (which is still much faster than chameleon skin).
This question is one of a long, ever-growing list of questions that they have. Take the leucophores: why are the reflectin proteins built into spheres in some places and plates in others? And how does the cuttlefish skin manage to stretch its limited number of pigments out without them fading? After all, it’s expanding those chromatophores to as much as five times their resting size, to a point where the pigment granules inside each cell are only three granules deep. And yet, the colors keep their same deep intensity. That’s why optical physicists like Hu think that the cuttlefish skin must be fluorescing in some way—generating its own glow. While scientists studying the cuttlefish have shed some light on their ingenious nanoscale mechanisms, there’s still much about which they’re still in the dark.
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Still, the progress that biologists are already making in understanding the cuttlefish’s physiology is why engineers like Kit Parker have taken an interest. Imagine this ability, woven into clothing that could change color depending on the environment. In Parker’s lab, something of a three-headed chimera where students are working on everything from organs-on-a-chip to grow-your-own-meat to super-fibers, there’s a little pink cotton-candy machine that one of his postdocs actually first used to show that nanofibers could be spun with much cheaper processes. One of the students hands me an Iron Man doll whose torso and muscular right calf have been thickly wrapped in what looks a little like that fake cobwebbing that homeowners hang on suburban shrubbery during Halloween. It feels smooth and almost rubbery to the touch. Perhaps one day, if the researchers could figure out how to use color-changing chemicals and proteins, they could potentially weave them into clothing using a spinning apparatus just like that, Parker says.
It’s fascinating stuff, outlandish ideas kick-started on a tiny budget (for which the cotton-candy machine stands as evidence), before someone decides the proof of concept is worth putting some money behind. That’s the constant struggle, Parker says, though he argues that operating on such shoestring conditions is what forces him and his researchers to innovate. Necessity is the mother of invention.
It might also explain why there are such different biotech-related projects going on in his lab—they’re always looking for new opportunities, no matter what direction it takes them. And that’s partly why Parker thinks that the first place that cuttlefish-based tech will make inroads is not in combat, but in fashion.
He might be right about that. That’s probably where a lot of the money is, he says, walking me across the Harvard campus, on his way to meet a busload of visitors from a company in Thailand interested in the meat-making potential of his synthetic muscle research. (Like I said, his lab is all over the place.) Certainly cosmetics companies like L’Oréal, inspired by iridescent butterfly wings, have harnessed the power of structural color for a shade-shifting line of eyeshadow. “Photonic make-up,” they call it.
The cuttlefish’s impressive camouflage may have developed as a response to predation, but it has been able to use its skin for a whole other purpose: wooing mates. Males will use their adaptive coloration to create impressive moving bands of light and color that look kind of like a psychedelic sunset in fast-forward, on repeat: pinkish reds and blue hues run across its surface. Even when they’re not showing off, they reveal a remarkable mastery of color and pattern (and some canny strategizing, to boot). While studying the mourning cuttlefish, Sepia plangon, biologist Culum Brown of Australia’s Macquarie University discovered that the males would cross-dress: the half of the male’s body that was facing the female would have a large-scale mottled pattern, typical of males; but the other half of its body, facing another male, would be covered in a zebra-striped female pattern! This tactic is thought to give the smaller males a fighting chance to impress the girl before the bigger guys notice. If that isn’t a premise for a good animal-kingdom rom-com, I don’t know what is.
As I’ve mentioned before, using their color-changing skills to show off comes in very handy to capture easily awestruck fish and crabs. Go to YouTube and look up something like “cuttlefish” and “hypnotize.” You have to see it to believe it. Even as I rewatch it for the umpteenth time, it’s hard to fathom how a living being can do this naturally.
The point in swooning over this indescribably beautiful light show is that the animals are harnessing the same mechanism they use to blend into the background to do the opposite: to stand out from the proverbial crowd. It’s strangely similar to the way that military camouflage has been repurposed as a fashion statement. Walk down a crowded city street and you’re bound to find someone wearing a camo pattern as a fashion accessory: as a jacket, on bandannas, at the beach, on workout capris, even on bikinis. (Even as I sat writing this in a café on Sunset Boulevard in Hollywood on a hot summer day, a girl came walking past my window with two friends, wearing tiny light denim shorts and a green camo-print top that was essentially a glorified sports bra. I don’t want to embellish, so to speak, but I have the vague sense that there was also a belly button ring involved.) Camo might be used to blend in, but it can also be used to make a very loud statement. It happens in nature, and it happens in human fashion: the green-and-brown mottled pattern once meant to help soldiers blend in is now used by civilians to stand out.
Fashion seems to have its own set of rules, an internal logic that, at least from season to season, defies physics, economics, and even aesthetics. It does, however, have one interesting similarity to the natural world: strange mutations in an aesthetic appear to pop up every year, and some of them do well and spread, while others die right on the catwalk. In that respect, it’s a little—a very little, admittedly—like natural selection. Clothing is like a second skin—and yet we don’t take full advantage of it, and make it multifunctional, the way a cuttlefish’s skin is. Nature is very good at multipurposing parts, and recruiting one piece of the anatomy for more than one function.
With cephalopods in mind, Parker has taught a class whose undergraduate students teamed up with Los Angeles–based fashion house Rodarte to design interactive dresses laced with fiber-optic light and color. One of the three designs responded to the earth’s magnetic field, changing colors as the wearer rotated. Another put on a light show in sync with the speed of its owner’s heartbeat; and a third responded to the level of sound in the room. Two of the dresses could even “speak” to each other using radio frequencies, trading colors if both of their owners agreed. (It’s an idea that seems to be catching on: A similar dress, made by IBM Watson and designer label Marchesa for the 2016 Met Gala, analyzed the emotions of Twitter conversations surrounding the event and adjusted its colors accordingly.)
Hanlon is also interested in the fashion aspect of cuttlefish camouflage; he’s got a high-end, well-known designer visiting his lab the next month, he says, but he won’t say who. I wager a wild guess. “Vera Wang?” But Hanlon shakes his head; he’s not playing. Fashion is serious business, after all.
More broadly, Hanlon’s interested in the art and aesthetic aspect of the cuttlefish. He has co-taught a class held both at Brown University and the Rhode Island School of Design in Providence that brought a mix of students together: artists as well as engineering, neuroscience, and computer science students. One of the major projects Hanlon assigned them: design a two-dimensional background, any kind, and then take a three-dimensional object and paint it so that it blends in. One art student quilted together a tapestry of random triangles and trapezoids and other shapes, all in different shades of blue. Then she made herself the 3D object, designing a dress and painting her face in a chaotic cerulean shattered-glass pattern. Striking as she was, she seemed to blend right into the background. Hanlon, who has had artists-in-residence on and off for the past four years, said she would probably end up doing a stint at MBL.
“How did she get the right shades of blue for her face?” I ask.
“No, no, no, that’s not how camouflage works!” Hanlon says. (Clearly I haven’t been getting the message.) “You can’t just put a uniform color on uniform background, there’ll be edges and shadows—that does not work. You have to be far more clever than that.”
* * *
Before we go further, I need to tell you something shocking about the cuttlefish: it’s color-blind.
It’s true. These masters of disguise, the same animals that can generate a whole palette of shades, from blues to browns to pinks and whites, who seem to blend into the background wherever they wander, whose eyes can actually see polarized light—they cannot see color. Hanlon’s group and other labs tested the animals by, for example, putting them in a tank covered in purple and yellow stripes. The purple and yellow were exactly the same brightness, so that there was technically no contrast between them; if you converted the image to black-and-white, the background would look like a stripeless, uniform gray.
The animals did not respond at all to those stripes. They didn’t put on a pattern, they didn’t raise their arms; nothing happened. Hanlon and colleagues tried again, this time with a large-scale blue-and-yellow checkerboard pattern. Presumably, the animals would put on their disruptive white square, the way they did for the large black-and-white checkerboard. But again, the blue and yellow were the exact same brightness, and instead of putting on a contrast pattern, the animal put on a uniform pattern, as if it were looking at a featureless surface.
The cuttlefish eye, one of the most highly developed light-sensing organs in the invertebrate animal kingdom, is a very different organ from our own. In the retina, humans have photoreceptors called “rods” for black-and-white vision, and cones with three different color-detecting pigments. But behind the cuttlefish’s cursive-W-shaped pupil lies just one receptor, which is most receptive to wavelengths of light at 492 nanometers—which translates to a sort of sea-foam green. (That’s actually why the researchers used a blue-and-yellow checkerboard for the second experiment: Since blue and yellow overlap with green, it would give the cuttlefish the greatest chance to see the checkerboard, if it could. The fact that it appeared to see nothing, then, seems even more damning now.)
This finding was shocking, for two reasons. One, many of the cuttlefish’s predators can see color. Predators of all kinds are highly visual: smell and sound may lead you in the right direction, and even “touch” can be of use—alligators and crocodiles have pressure sensors that pick up subtle disturbances in murky water from prey movements. But when it comes to nabbing a quick-moving meal, eyes are usually what get you the prize.
Two, Hanlon and other research divers have seen, over and over again, how cephalopods—particularly octopuses and cuttlefish—appear to match the disparate shades of the sand, rocks, coral, and algae around them. If they really can’t see these colors, it almost seems like a cruel joke by Nature herself—that the animal that relies so completely on camouflage can’t predict what its predators (or its prey) may see.
But Hanlon is not entirely convinced that the cuttlefish can’t see any color. He and his colleagues Lydia Mäthger and Steven Roberts found something strange: The genetic instructions for opsin, the light-detecting protein in the retina of the eye, were found on the skin of its belly and the tutu-like fin frilling its body. The light-detecting proteins were concentrated around the chromatophores. Hanlon thinks the opsins might have something to do with the animal’s incredible matching ability, in spite of being colorblind, though it’s unclear exactly how it would work: the opsin proteins are also tuned to a light wavelength of 492 nanometers, which means it would probably not be able to see much other than sea-foam green. But Hanlon’s still convinced that there’s more going on than meets the eye (so to speak). The opsins appear to be concentrated in the cell types that make up chromatophore organs, along with two or three other molecules found in the eye.
“The equipment seems to be there to detect light,” Hanlon says.
The problem is, they haven’t yet been able to prove that this is what’s happening. Establishing a link between these eye proteins and particular behavior in the cuttlefish has proved highly elusive.
Proven or not, it was an idea that caught the attention of John Rogers, who met Hanlon through a basic research challenge being run by the U.S. Navy and began to read his papers in depth—to a level that surprised and impressed the biologist.
“I mean a lot of people say, ‘I see it, I saw your talk,’ but they don’t read the papers. So when he read the papers, he got it,” Hanlon said. “Within five minutes, I knew this guy had it really figured out.”
Rogers is a materials scientist and engineer at the University of Illinois at Urbana-Champaign. I’d spoken to him before about the devices he builds, including electronic “tattoos” that, applied to the skin, can monitor your heart, brain, and muscle activity. The man knows how to make circuits that work on skin; so perhaps it wasn’t as much of a stretch (so to speak) to create devices that work a little like skin, too. He doesn’t just create flexible devices—he’s a flexible thinker, too, one with a deep interest in biology. The cuttlefish was no exception.
“The kinds of things that they can do are just absolutely mind-boggling so as an engineer, it’s utterly humbling,” Rogers said. “So you look at that, you talk to Roger, you realize immediately, we are not going to be able to replicate that type of system at any kind of detailed level.”
Pretty modest words for a guy who was awarded a MacArthur “genius grant” in 2009. Somebody out there clearly thinks that he’s got good ideas for the future of electronics. But Rogers says he’s just trying to be practical—and to consider what his expertise can bring to the table.
“We can think of it in an abstract sense,” Rogers said. “What is the overall architecture, what are the functional layers and how are they talking to one another, and try to pull out those ideas and embed them in the kind of systems that we do know how to make.”
Here’s the catch with cuttlefish skin: It requires a really big brain. To be able to control a skin that’s shot through with so many nerve endings, the cuttlefish must have tons and tons of neurons, which is probably why the Coleoidea—the order of cephalopods made up by the cuttlefish, octopus, and squid—are the smartest invertebrates around. Scientists have put cuttlefish in mazes and watched them quickly learn how to navigate these spatial puzzles. And they can certainly problem-solve in the real world. If two burly males, competing for the attentions of a female, are engaged in a multicolored camo-off, the smaller males will sometimes put a female pattern on their bodies to get close to the female and mate with her. (And the female often goes for it, apparently preferring brains over brawn.) The clever and cunning octopus tends to get all the academic accolades, but the cuttlefish is no slacker.
If you’re trying to build synthetic, skinlike camouflage, however, you don’t want to have to carry around a bulky electronic brain (i.e., a computer) to have this thing work. After all, it’s hard enough creating synthetic skin that can use adaptive camouflage—imagine having to pair it with a computer processor and cameras. Imagine having to also design and build the programming, and to connect the “brain” and “eyes” to the skin. Imagine all the ways in which that bulky system could break down. This is a fundamental roadblock in actually building a working synthetic model.
Rogers, after reading Hanlon’s papers on the potential of opsins, realized something: The opsins provided a solution to the light-sensing problem. If you distributed the light sensing, the way Hanlon and his colleagues believed (but could not prove) was happening, then you didn’t need to depend solely on a central hub to watch the environment and react accordingly. The skin itself could do some of that work.
“It really is a bit of genius in my view,” Hanlon said. “He looked at the layering and based it more or less as much as he could on cephalopod skin, but he took this next element, which we’ve been trying to prove for four years but don’t have definitive evidence for … and he said, ‘Now that’s something I can do, whether biology does it or not.’”
The prototype Rogers and colleagues came up with was a layered structure, like cephalopod skin. The upper layer’s pixels are filled with a temperature-sensitive ink that is black at cooler temperatures but clear when heated above 116 degrees Fahrenheit. This was analogous to the pigment-filled chromatophores. Beneath that was a layer of silvery-white tiles, which could only be seen when the black dye was turned off, analogous to the leucophores. Beneath this layer were thin silicon circuits that could heat up the dye layer to turn it transparent; these were analogous to the muscles that turned the chromatophores on or off. Underneath that was a layer of photoreceptors—akin to the opsin proteins distributed through the animal’s body. The skin was able to respond in one to two seconds to changing visual stimuli, from triangles and moving squares to a digital “U of I” logo. The whole thing is a mere 200 microns or so thick, about twice the width of a human hair, and it works even when you wrap that skin on curving surfaces. For now, the device is only in black-and-white, though Rogers says there’s no reason they can’t ultimately find ways to make their synthetic skin responsive to color.
The list of applications these sort of devices could be good for is enough to make any tech-savvy entrepreneur drool. Such thin sheets could be applied to military vehicles to help them blend in. On the walls of homes and offices, it could be a combination camera and color-tunable wallpaper, perhaps responsive to the ambient light in the room. Rogers talked to his colleagues at the school of architecture, who pointed out that this could be useful for all kinds of surfaces, and not just flat ones—ceilings, tables, other pieces of furniture. The technology may even draw from and perhaps influence the way e-readers and television screens are designed. Like Hanlon and Parker, Rogers has also been talking to a professor of fashion design at the Art Institute of Chicago about the possibilities in fashion and design.
“The disconnect there is that we cannot make a dress. We can make a one-square-inch swatch,” Rogers said, with a rueful laugh. His device is about the thickness of paper, and you can’t make a dress out of something the consistency of paper. “She gets excited about stuff and wants us to build pants or something, you know. We’d love to do that—but I’d have to kill a few postdocs before that would happen.”
Military applications are just as far off into the future, and not his purview in this research, Rogers added. He, and others also working with the U.S. Navy program, are simply looking at the basic science; this device he created is just a proof of concept that such layered, responsive, color-changing devices are possible. His device only works in black-and-white, but colored component layers could be added in or switched out over time. Using heating circuits isn’t the best way to force a color-transition, he added—it wastes quite a bit of energy. But the device gives other researchers a modular template they can use and modify over time, a framework in which to proceed with their own basic research.
All this begs the question, though—does Rogers’s innovation count as entirely bioinspired? After all, the opsins’ function hasn’t been proven; what if that’s not how it works? There are long-simmering arguments over what biomimicry means, what bioinspiration means, and what it says about the type and level of science being done, which we’ll start to touch upon in later chapters.
Hanlon, for his part, says it does. After all, the insight that led to using the distributed photodetectors only came from studying nature, the biologist says. Whether or not it turns out to be 100 percent accurate is almost beside the point.
Copyright © 2017 by Amina Khan
