Here in Bloomington, the time of cicadas is drawing to a close.
Some trees are still fairly loud, with pulses of sound that pour down, compressing & rarefacting the air like the thrum of an alien turbine. But two weeks ago, the loudest trees were excruciating, with sound levels that could dispel all thought, inducing headaches & nausea as we walked beneath.
More & more often now, I’m able to pick out the plaintive kreeee of individual singers, their voices divorced from any chorus: males who arrived late to the party and are wondering whether any nearby females might be similarly tardy.
Molted exoskeletons still litter the ground, or cling to flowerstems & the lower bark of trees. But my kids are finding few fresh ones. Nearly all the cicadas who are going to emerge in our town this year have already done so.
My kids (like most kids) collected the shed exoskeletons. And each morning before school, they would search our carport for newly emerged adults – although it does feel strange to refer to cicada nymphs as somehow youthful when they’re a decade older than my eldest child. She cradled the bugs like babies; they were more than twice her age.
My kids would move the newcomers – bodies & wings still soft from metamorphosis – to a safe sunny spot in our yard. They’d be able to fly sooner, & our car wouldn’t squish them.
In the afternoon, we would go on walks – again stepping carefully to avoid squishing anyone – and we’d stop every few feet to inspect the cicadas whom we found.
And it was alarming. Most of the insects we encountered then were oddly shaped, with twisted legs or crumpled wings; or exceptionally small; or otherwise malformed. We found some who had only partially emerged from their exoskeletons and then stopped, trapped within their own old skin.
Which I can’t chide them for too severely. At times, we humans also have difficulty sloughing off our past selves.
Now that the cicadas’ brief orgy is ending, they will expire. Many have already died: not just the cicadas who were eaten by birds, chipmunks, squirrels, pet cats & dogs, but also the cicadas who simply plummet from the sky, collapsing from the various internal depredations of old age.
They decompose. The air reeks now of an acrid ammonia tang. On certain sidewalks – beneath especially popular trees, those that a few days ago had been deafeningly loud – we walk through a bevy of corpses. Viscous goo spills from their split sides where other people have stepped on them.
And it’s interesting, the perspective that my children and I have had upon the cicadas’ lives.
For all those years, they were invisible to us, burrowing rootward through the soil and sipping the delectable sap of trees.
After the cicadas emerged, we still rarely saw the cicadas who were feeling actualized. Who were up high in the trees, singing, seducing, laying eggs, living their best cicada lives. Those who lingered on the sidewalks where we might find them had often suffered some mishap or misfortune. Cicadas whose heads had been bitten off by birds. Cicadas who were bamboozled by the sky’s reflection in a puddle or pool of water and plunged in to drown. Cicadas whose developmental differences left them unable to fly.
I felt really happy that my children, even after interacting with thousands of cicadas, still felt compelled to help each and every one. My children never stopped searching the carport to ensure that nobody would be squished. If any cicadas fell into nearby water, my children would splash in to the rescue.
But it felt strange for me, knowing the limits of our perception. As though some insects had visited a human hospital and drew all their conclusions about our way of being based on what they saw there.
For people whose past cultural experiences have led them to associate mint smells with sweet tastes, pairing the scent of mint with a sip of sucrose solution makes them believe that the drink is more sugary than it really is. When mint scent is paired with a sip of mildly acidic water, the drink seems less sour than it really is.
This experiment didn’t assess people’s perception of alcoholic drinks, but people in the United States probably make the same mistake about the bourbon in a mint julep.
Our assumptions – particular to our own cultural experience of the world – can powerfully deceive us.
A mint julep mixed perfectly for someone from the United States would taste bitter to someone from Vietnam.
Viet Thanh Nguyen – author of The Sympathizer, which I’ve written about previously – strives to draw attention to our cultural blindness. The way our minds’ innate self-deceptions allow us to overlook or misinterpret the experiences of others.
My spouse and I have often felt grateful for Nguyen’s work. His essay about the sinking sensation he felt after teaching his child to read was particularly beautiful. (I linked to it in my own essay about teaching a child to read.)
Which is why we felt so dismayed by Nguyen’s most recent New York Times editorial.
Nguyen explains why he enjoys teaching over Zoom. He’s prompted with students’ names; he can see their reactions up close; student voices contribute to the lecture from the same up-front position of power as his own; typed remarks can overlap without distracting; lectures are recorded for students to review later.
All well and good. Nguyen is quite intelligent. If he thinks Zoom is good for lectures, I’m inclined to believe him.
But lectures aren’t the best way to learn.
For many subjects, project-based learning is a more effective way to educate students. Many of my spouse’s resources – designed primarily for teaching college-level biology and introductory Earth & space science with a social justice bent – are available on her website, here.
For the better part of a decade, I’ve hosted a poetry class in the county jail. We read poems and discuss how they make us feel. Our discussions touch upon contemporary scientific research, mythology, economics – all safe enough topics, for most folks – but also religion, addiction, trauma, violence, relationships, loss – which can be tough for anyone to talk about, let alone a room full of men who won’t get to see their families for months.
Because people cycle through the county jail, I never know who will be coming to class each week until I get there. For a few months, I might be with mostly the same group of men. Other weeks, I won’t have met any of the dozen or so people previously.
And there’s a huge difference between what we can accomplish – between what sorts of things feel safe to discuss – when the people in class haven’t met me before, and haven’t been in a class like that with each other. If we haven’t built the necessary emotional connection, we can do less. The class is worse for all of us.
Recently, the jail has allowed a small number of classes over Zoom. But Zoom doesn’t let you make the same emotional connection.
People sometimes complain about the supposed invasiveness of Zoom – the camera snatches up your personal surroundings, the pictures on your wall, the books on your shelves, your family in the background – but it’s by no means the intimacy of being there.
My spouse says, “Over Zoom you can’t tell who’s hungry.”
It would be nice if she meant this metaphorically – that it’s hard to tell who’s eager to learn. But, no. Many students aren’t eating enough. They are hungry.
Worse, we read Nguyen’s paean to Zoom on a snow day.
Streets near my spouse’s high school school were well-salted and plowed, but we live in a sprawling, semi-rural area – the school district serves families from a mix of socioeconomic backgrounds. There are hills and valleys – not everyone can get a satellite signal at home. And the for-profit cable companies certainly haven’t connected those families to the modern world with wires.
Still, the pandemic has made “e-learning days” seem like a reliable alternative. If it snows, kids learn from home.
“What’s Zoom supposed to do,” my spouse asked, “for my students with no heat?”
This isn’t (only) a concern for fluke events like the avarice-fueled power outages and heat losses in Texas. My spouse grew up in Albany, New York. Every winter was cold. The infrastructure to heat homes there was secure – for children whose families had money.
My spouse’s family didn’t. Her father failed to pay the electric bill. The power was shut off. And then the district called a snow day.
If my spouse and her sibling had gone to school, it wouldn’t have been so bad. Warm classrooms, a hot meal.
Instead they were stuck at home, shivering. Wanting so badly to go to a neighbor’s house. But then the neighbors would know.
In the United States, where poverty is often stigmatized as a moral failing, people hide the ache of want.
Which is why Zoom is so horrible. Zoom makes it easy. When you only have to disguise a small corner of your life, you can convey the illusion that things are okay.
A man in my poetry class recently told me, “Ugh, cocaine is awful. You use some, you’ll want some more, but I hate it. It makes me such a jerk. I mean, I’m not like this, I’m never like this, but if I’m on coke, I’m like, bitch, you best make yourself useful around here.”
Cocaine has a reputation as a fun party drug, but nobody in jail has anything nice to say about it. And it’s not that they’re down on drugs in general – that same man told me:
“Meth? Meth is great – you should never try it.”
And then he explained the social niceties of trying to shoot up in the home of a friend who was recently diagnosed with HIV. This friend was apparently cavalierly sloppy with needles:
“Like, blood was spurting, and I was scooting back thinking, like, god, I wish I was anywhere but here … “
European eels are endangered. They swim huge distances to complete their life cycles – hatching at sea, undertaking a voracious (oft cannibalistic) quest up rivers, then returning to their birthplaces to spawn – and have been thwarted by hydroelectric dams blocking their migration, and the tendency of an insatiable terrestrial ape to catch and consume huge numbers of their kind.
Now these eels face another obstacle: they must complete their voyages while blitzed on cocaine. European governments dump drugs into the sea to “destroy” them, but that’s not how water works. The drugs are still there. The eels get high.
According to popular legend, Robert Louis Stevenson was very sick before he wrote his Strange Case of Dr. Jekyll and Mr. Hyde.
Stevenson had tried many cures; all had failed. Then his spouse bought cocaine. This worked. Suddenly Stevenson could write again. In three days, he composed his novel.
When he read the first draft to his spouse, she said it didn’t seem sufficiently allegorical. So Stevenson flung the pages into the fire and began again. In three more days, he’d composed the version of the story that we know today.
Dr. Jekyll was a fine man. On drugs, he became a monster.
When our first child was just shy of two years old, she liked to wear a green long-sleeve with a picture of The Incredible Hulk rampaging. She’d pull it from her drawer; I’d say, “Oh, you want to wear your Hulk Smash shirt today?”
One day, I asked her, “N., why does Hulk want to smash?”
She looked down at the picture, then back up to me. First she signed the word hungry.
“Oh, Hulk wants something to eat?”
She shook her head. No, that didn’t sound quite right. She looked down again, then made another sign, banging her hands together for the word shoes.
“Hulk is upset because he has no shoes?”
She bobbed her head yes. No shoes. That would make her rage, too.
Once, some runners on the local high school cross country team asked me who would win in a fight, Superman or the Hulk. They’d reached a detente after one claimed that the Hulk was unstoppable when enraged (“… and nothing calms him down except his girlfriend.”), and the other argued that Superman could turn back time until the moment before Hulk had gotten angry, then smash him.
I demurred. I don’t think Superman is a very interesting hero, and the Hulk is interesting only in campaigns, not battles. I like the idea of a hero who might go berserk and accidentally thwart his own plans, but a single bout of wrestling isn’t like that. I think it’s more compelling to consider his constant risk of hurting the people that he loves.
In Educated, Tara Westover writes beautifully about the horrors of living with the Hulk. Her early years were controlled by a father in the throes of extreme paranoia and delusions of grandeur:
Fourteen years after the incident with the Weavers, I would sit in a university classroom and listen to a professor of psychology describe something called bipolar disorder. Until that moment I had never heard of mental illness. I knew people could go crazy – they’d wear dead cats on their heads or fall in love with a turnip – but the notion that a person could be functional, lucid, persuasive, and something could still be wrong, had never occurred to me.
The professor recited facts in a dull, earthy voice: the average age of onset is twenty-five; there may be no symptoms before then.
The irony was that if Dad was bipolar – or had any of a dozen disorders that might explain his behavior – the same paranoia that was a symptom of the illness would prevent its ever being diagnosed and treated. No one would ever know.
Because her father was at war with the federal government, Westover never went to school. Her birth went undocumented – she didn’t have a certificate that would’ve allowed her to enroll until years later, and even then wound up with a hodgepodge of documents that listed slightly differing names and birthdates.
And her father needed money, because he was frantically stockpiling food and ammunition. He needed solar panels (back when they were much more expensive than today) because the power grid was going to cut out after Y2K.
As one of God’s soldiers, he needed to build an ark. Or tank. Arsenal. Whatever.
This constant hustle for money led Westover’s father to subject his children to incredible dangers. There might be a safe way to do a job, but if the risky way could save two minutes, the man put his kids’ lives on the line. Westover was forced to ride up to a trailer inside a bin filled with two thousand pounds of scrap iron. When her leg got caught and she couldn’t jump out, her father still dumped the bucket. Westover tumbled nearly twenty feet to the ground. And this was lucky. If she’d fallen a few inches to the other side, she would’ve been crushed by all that iron.
Her brothers were injured even more grievously at her father’s hands.
For instance, a brother’s clothes caught fire while he was working with his father. In Westover’s recollection, the father then lifted his burnt son into the cab of a truck and made him drive home alone. Only the ten-year-old Westover was there to help him, so she put her brother’s burnt leg inside a garbage can full of ice water.
If Dad had been with Luke on the mountain, he would have brought him to the house, would have treated the burn. Dad was away on a job somewhere, that’s why Luke had had to get himself down the mountain. Why his leg had been treated by a ten-year-old. Why it had ended up in a garbage can.
Except that she then realizes that her father must have been with her brother. He must have been there in order to put out the fire; otherwise the whole mountainside would’ve burned.
In a footnote, Westover adds:
Since the writing of this story, I have spoken to Luke about the incident. His account differs from both mine and Richard’s. In Luke’s memory, Dad took Luke to the house, administered a homeopathic for shock, then put him in a tub of cold water, where he left him to go fight the fire. This goes against my memory, and against Richard’s. Still, perhaps our memories are in error. Perhaps I found Luke in a tub, alone, rather than on the grass. What everyone agrees upon, strangely, is that somehow Luke ended up on the front lawn, his leg in a garbage can.
Westover’s father was abusive, and he routinely convinced his children that their memories were in error, instead substituting his own (oft-illogical) versions of events, but he isn’t the Hulk in this story. Yup, things get worse. One of Westover’s brothers might suddenly snap and become Hyde.
Westover loved her older brother Shawn, but during an over-hasty job with their father, Shawn fell twelve feet, striking a concrete wall headfirst, and sustained a severe brain injury. Instead of taking the kid to the hospital, their father propped him against a pickup truck and left him to sit in the hot sun.
His pupils were unevenly dilated. His brain was bleeding.
Fifteen minutes later, Shawn wandered back to the worksite and started acting wild. He screamed, flung his father, ran around leaping and howling. The others tackled him – at which point his head again struck the concrete, hard – and called 911 for a helicopter to airlift him to the hospital.
It took some time for me to realize that although Shawn looked the same, he wasn’t. He seemed lucid, but if you listened carefully his stories didn’t make sense. They weren’t really stories at all, just one tangent after another.
Worse, he was violent. But unpredictably so. At one moment, he and Westover might be laughing together. At another moment, he’d twist her arm behind her back so brutally that she worried her wrist would break, call her a slut, and cram her face into a toilet bowl. He hacked at the throat of his son’s pet dog with a five-inch knife blade while the animal howled, dying. He called his sister and placidly explained his plans to visit her university and murder her.
In a lucid moment, he helped Westover install a massive deadbolt in her bedroom door, despite knowing that he was the only person she needed protection from.
And yet, Westover escaped. Although she’d never set foot inside a classroom, she was accepted to Brigham Young University, where the consensus view of reality was much closer to her own.
Of course, she made a few stumbles. Because she didn’t understand what course numbers signified, she enrolled as a freshman in an upper-level art history class. Worse, she raised her hand to ask after the meaning of a word she didn’t recognize: Holocaust.
During one of my own classes, we were discussing poems from Charles Reznikoff’s Testimony when I mentioned that Reznikoff had also written about the Holocaust.
“Holocaust, what’s that?” a man asked.
Unlike Westover, this man had grown up in an urban area. But he’d stopped attending school when he was pretty young, and there’s a lot of cultural knowledge that we tend to take for granted.
I’d like to think that I handled the situation better than Westover’s professor. Westover was shamed. In our poetry class, we instead talked about how the word “holocaust” could be seen as offensive when used to describe the years during which members of the Nazi party murdered at least 6 million people, typically because their victims believed in Judaism. The word “holocaust” originally meant a burnt offering for God, so Jewish leaders instead referred to this period of history with the Hebrew word for “catastrophe.” Although even that phrasing seems off, because “catastrophe” generally evokes natural disaster, whereas the Holocaust was mass murder and torture on a scale comparable only to American slavery. A purely human evil.
Westover became a historian. After experiencing firsthand the nightmare of having her own account of reality constantly replaced by someone else’s version, she understood how powerful storytelling can be. Educated is a beautiful book. And, to my mind, a much more sensible depiction of unequal opportunity in the United States than J.D. Vance’s Hillbilly Elegy.
Westover recognizes how lucky she was to escape, and how narrowly she avoided the fate of her sister-in-law. And Westover gives a powerful endorsement of government aid:
I began to experience the most powerful advantage of money: the ability to think of things besides money. My professors came into focus, suddenly and sharply; it was as if before the grant I’d been looking at them through a blurred lens. My textbooks began to make sense, and I found myself doing more than the required reading.
Peering with the unwavering focus of a watchful overlord.
A cat could seem to be many different things, and Brendan Wenzel’s recent picture book They All Saw a Cat conveys these vagrancies of perception beautifully. Though we share the world, we all see and hear and taste it differently. Each creature’s mind filters a torrential influx of information into manageable experience; we all filter the world differently.
They All Saw a Cat ends with a composite image. We see the various components that were focused on by each of the other animals, amalgamated into something approaching “cat-ness.” A human child noticed the cat’s soft fur, a mouse noticed its sharp claws, a fox noticed its swift speed, a bird noticed that it can’t fly.
All these properties are essential descriptors, but so much is blurred away by our minds. When I look at a domesticated cat, I tend to forget about the sharp claws and teeth. I certainly don’t remark on its lack of flight – being landbound myself, this seems perfectly ordinary to me. To be ensnared by gravity only seems strange from the perspective of a bird.
There is another way of developing the concept of “cat-ness,” though. Instead of compiling many creatures’ perceptions of a single cat, we could consider a single perceptive entity’s response to many specimens. How, for instance, do our brains learn to recognize cats?
My friend looked at me with a mix of puzzlement and pity and said, “No.” Then added, as regards Philosophical Investigations, “You read it too fast.”
One of Wittgenstein’s aims is to show how humans can learn to use language… which is complicated by the fact that, in my friend’s words, “Any group of objects will share more than one commonality.” He posits that no matter how many red objects you point to, they’ll always share properties other than red-ness in common.
Or cats… when you’re teaching a child how to speak and point out many cats, will they have properties other than cat-ness in common?
In some ways, I agree. After all, I think the boundaries between species are porous. I don’t think there is a set of rules that could be used to determine whether a creature qualifies for personhood, so it’d be a bit silly if I also claimed that cat-ness could be clearly defined.
But when I point and say “That’s a cat!”, chances are that you’ll think so too. Even if no one had ever taught us what cats are, most people in the United States have seen enough of them to think “All those furry, four-legged, swivel-tailed, pointy-eared, pouncing things were probably the same type of creature!”
Even a computer can pick out these commonalities. When we learn about the world, we have a huge quantity of sensory data to draw upon – cats make those noises, they look like that when they find a sunny patch of grass to lie in, they look like that when they don’t want me to pet them – but a computer can learn to identify cat-ness using nothing more than grainy stills from Youtube.
Quoc Le et al. fed a few million images from Youtube videos to a computer algorithm that was searching for commonalities between the pictures. Even though the algorithm was given no hints as to the nature of the videos, it learned that many shared an emphasis on oblong shapes with triangles on top… cat faces. Indeed, when Le et al. made a visualization of the patterns that were causing their algorithm to cluster these particular videos together, we can recognize a cat in that blur of pixels.
The computer learns in a way vaguely analogous to the formation of social cliques in a middle school cafeteria. Each kid is a beautiful and unique snowflake, sure, but there are certain properties that cause them to cluster together: the sporty ones, the bookish ones, the D&D kids. For a neural network, each individual is only distinguished by voting “yes” or “no,” but you can cluster the individuals who tend to vote “yes” at the same time. For a small grid of black and white pixels, some individuals will be assigned to the pixels and vote “yes” only when their pixels are white… but others will watch the votes of those first responders and vote “yes” if they see a long line of “yes” votes in the top quadrants, perhaps… and others could watch those votes, allowing for layers upon layers of complexity in analysis.
And I should mention that I feel indebted to Liu Cixin’s sci-fi novel The Three-Body Problem for thinking to humanize a computer algorithm this way. Liu includes a lovely description of a human motherboard, with triads of trained soldiers hoisting red or green flags forming each logic gate.
In the end, the algorithm developed by Le et al. clustered only 75% of the frames from Youtube cat videos together – it could recognize many of these as being somehow similar, but it was worse at identifying cat-ness than the average human child. But it’s pretty easy to realize why: after all, Le et al. titled their paper “Building high-level features using large scale unsupervised learning.”
When Wittgenstein writes about someone watching builders – one person calls out “Slab!”, the other brings a large flat rock – he is also considering unsupervised learning. And so it is easy for Wittgenstein to imagine that the watcher, even after exclaiming “Now I’ve got it!”, could be stymied by a situation that went beyond the training.
Unsupervised learning may be sufficient to prepare children for life in an agrarian village. Unsupervised learning is sufficient for chimpanzees learning how to crack nuts. And unsupervised learning is sufficient to for a computer to develop an idea about what cats are.
But the best human learning employs the scientific method – purposefully seeking out “no.”
I assume most children reflexively follow the scientific method – my daughter started shortly after her first birthday. I was teaching her about animals, and we started with dogs. At first, she pointed primarily to creatures that looked like her Uncle Max. Big, brown, four-legged, slobbery.
Eventually she started pointing to creatures that looked slightly different: white dogs, black dogs, small dogs, quiet dogs. And then the scientific method kicked in.
She’d point to a non-dog, emphatically claiming it to be a dog as well. And then I’d explain why her choice wasn’t a dog. What features cause an object to be excluded from the set of correct answers?
Eventually she caught on.
Seems toddler & I will just have to agree to disagree whether certain animals are Canis lupus (“Daa!”) or Sus scrofa (“Naw, that’s a pig!”).
Many adults, sadly, are worse at this style of thinking than children. As we grow, it becomes more pressing to seem competent. We adults want our guesses to be right – we want to hear yes all the time – which makes it harder to learn.
The New York Times recently presented a clever demonstration of this. They showed a series of numbers that follow a rule, let readers type in new numbers to see if their guesses also followed the rule, and asked for readers to describe what the rule was.
A scientist would approach this type of puzzle by guessing a rule and then plugging in numbers that don’t follow it – nothing is ever really proven in science, but we validate theories by designing experiments that should tell us “no” if our theory is wrong. Only theories that all “falsifiable” fall under the purvey of science. And the best fields of science devote considerable resources to seeking out opportunities to prove ourselves wrong.
But many adults, wanting to seem smart all the time, fear mistakes. When that New York Times puzzle was made public, 80% of readers proposed a rule without ever hearing that a set of numbers didn’t follow it.
Wittgenstein’s watcher can’t really learn what “Slab!” means until perversely hauling over some other type of rock and being told, “no.”
We adults can’t fix the world until we learn from children that it’s okay to look ignorant sometimes. It’s okay to be wrong – just say “sorry” and “I’ll try to do better next time.”
Most writers spend a lot of time thinking about how others see the world. Hopefully most non-writers spend time thinking about this too. It’s easier to feel empathy for the plights of others if you imagine seeing through their eyes.
The algorithm shifts the color distribution of images to highlight which objects appear most distinct for an animal with different photoreceptors. I thought it was cool even though the processing they describe fails in many ways to convey how differently various animals perceive the world.
For one thing, image processing can only affect visuals. Another species may rely more on sound, scent, taste (although perhaps it’s cheating to list both scent and taste — they are essentially the same sense, chemodetection, with the difference being that humans respond more sensitively, and to a wider variety of chemicals, with our noses than our tongues), touch, sensing magnetic fields, etc.
If we assume that other animals will also place maximal trust in the detection of inbound electromagnetic radiation from the narrow band we’ve deemed “the visual spectrum,” we can fool ourselves regarding their most likely interpretations. For an example, you could read my previous post about why rattlesnakes might assume that humans employ chameleon-like camouflage (underlying idea courtesy of Jesus Rivas & Gordon Burghardt).
The second problem with assuming that an image with shifted colors represents how another animal would view the world is on the level of neurological processing. When a neurotypical human looks at an image and something resembles a face, that portion of the image will immediately dominate the viewer’s attention; a huge amount of human brainpoweris devoted to processing faces. Similarly, some dogs, if another dog enters their visual field, have trouble seeing anything else. And bees: yes, they see more blues & ultraviolets than we do, but it’s also likely that flowers dominate their attention. I imagine it’s something like the image below, taken with N and her Uncle Max on a recent walk. Although, depending on your personality, you might have some dog-style neurological processing, too.
Even amongst humans this type of perceptual difference exists. A friend of mine who does construction (ranked the second-best apprentice pipefitter in the nation the year he finished his training, despite being out at a buddy’s bachelor party, i.e. not sleeping, all night before the competition), when he walks into a room, immediately notices all exposed ductwork, piping, etc. Most people care so little about these features as to render them effectively invisible. And I, after three weeks of frantic itching and a full course of methylprednisolone, could glance at any landscape in northern California and immediately point out all the poison oak. My daughter can spot a picture or statue of an owl from disconcertingly far away and won’t stop yelling “owww woo!” until I see it too.
The color processing written up in the New York Times, though, was automated. Given the current state of computerized image recognition, you probably can’t write a script that would magnify dogs or flowers or poison oak effectively. Maybe in a few years.
There’s one last big problem, though. And the last problem is about the colors alone. There is simply no way to re-color images so that a dichromatic (colloquially, “colorblind”) human would see the world like a trichromat.
Here’s how it works: most colorblind people are dichromats, meaning they have two different flavors of color receptors. Colored light stimulates these receptors differentially: green light stimulates green receptors a lot and blue receptors a little. Blue light stimulates blue receptors a lot and green receptors a little. The brain processes the ratio of receptor stimulation to say, “Ah ha! That object is blue!”
A typical human, however, is a trichromat. This means that the brain uses three datapoints to determine an object’s color instead of two. The red and green receptors absorb maximally near the same part of the spectrum, though… the red vs. blue & green vs. blue ratios are generally very similar. So the third receptor type mostly helps a trichromat distinguish between red and green.
This means a dichromat will have a narrower range of the electromagnetic spectrum that they are good at distinguishing color within. For a dichromat, reds and greens both will be characterized by “green receptor stimulated a lot, blue receptor only a little.”
Now, if you imagine that the visual spectrum is number line that runs from 0 to 100, a dichromat would be good at distinguishing colors in the first 0 to 50 segment, and not good at distinguishing color beyond that point — everything with green wavelength, ca. 500 nanometers, and longer, would appear to be green.
But you could take that 0 to 100 number line and just divide everything by 2. Then every color would look “wrong” — no object would appear to be the same color as it was before you put on the wacky glasses — and you’d be less able to distinguish between close shades — if two colors needed to be 15 nanometers apart to seem different, now they’d need to be 30 nanometers apart — but a dichromat could distinguish between colors over the same full visual spectrum as trichromats.
That’s roughly how the glasses should work — inbound light is shifted such that all colors are made blue & greenish, and the visual spectrum is condensed).
Of course, even though you can’t change an image in a way that will allow you (I’m assuming that you, dear reader, are a trichromat. But my assumption has a 10% chance of being wrong. My apologies! I care about you, too, dichromatic reader!) and a dichromatic friend to see it the same way. But you can change your friend. You can inject a DNA-delivering retrovirus into your friend’s eyeball, and after a short neurological training period, you and your friend will see colors the same way!
It’s possible that your friend won’t like you any more if you do this. But here’s how it works: the retrovirus encodes for the flavor of photoreceptor that none of your friend’s cone cells were expressing. Upon infection, the virus will initiate production of that receptor… so now a subpopulation of cone cells will be sending new signals to the brain. They’ll be stimulated by different wavelengths of light than they were before. And brains, magically plastic things that they are, rapidly rewire themselves to incorporate any new data they have access to.
(If you’re interested in this sort of thing, you should look up biohacking. Like implanting magnets in your fingers to “feel” electric or magnetic fields. But I’m not going to link to anything. Wrestling your friend to the ground in order to inject recombinant DNA into his eyeball? That makes me smile. But slicing open your own fingertips to put magnets under the skin? That’s too creepy for me).
If a brain is suddenly receiving different signals after exposure to red versus green light, it’ll use that information. Which means: Color vision achieved! Unfortunately, viral DNA integrates randomly, so a weird eye cancer might’ve been achieved as well. You win some, you lose some.
What we call “color vision,” though, is still only trichromatic. With three flavors of cone cells, humans can do a pretty good job distinguishing colors from about 400 to 700 nanometers. But some species have more flavors of cone cells, which means they can distinguish the world’s colors more precisely. Even some humans are tetrachromats, although their fourth cone cell flavor is maximally stimulated by light midway between red and green, a part of the electromagnetic spectrum that trichromatic humans are already good at parsing. And tetrachromatic humans are rare: to the best of my knowledge no languages have a word for that secret color between red and green. I don’t know any words for it, at least, but maybe this too is a secret guarded by those who see it.
Still, no amount of image processing would allow you, dear reader, even if you’re one of those rare tetrachromatic individuals, to see the world in all the spangled glory seen by a starling or a peacock. This graph shows the stimulation of each flavor of cone cell receptor by different wavelengths of light.
And even the splendorous beauty seen by birds pales in comparison to the way we thought mantis shrimps perceive the world. Because mantis shrimps, see, have twelve flavors of photoreceptors, which means that if their brains processed colors the same ways ours do, by considering the ratio of cone cell flavors that are stimulated by incident light, they’d be exquisitely sensitive to color. Here: compare the spectral sensitivity graph for humans and starlings, shown above, to the equivalent graph for mantis shrimps. This makes humans look pathetic!
If you haven’t see it, you should definitely read this cartoon about mantis shrimp perception from The Oatmeal.
It’s possible that mantis shrimps process color differently from humans, though. Instead of computing ratios of cone-flavor activation to determine the color of an object, they might decide that an object is the color of whatever single cone flavor is most stimulated. In other words, while humans use stimulation ratios from our mere three flavors of cone cells to identify thousands of hues, a species with a dozen photoreceptor flavors might regard every object as being one of those dozen discrete colors.
Indeed, that’s what a recent study from Thoen et al. (“A Different Form of Color Vision in Mantis Shrimp”) suggests. They trained mantis shrimps to attack a particular color of light in order to win a treat, then tested how well it could distinguish that color from nearby wavelengths. In their hands, the shrimps needed approximately 50 nanometers separating two colors to distinguish them, whereas humans, with our meager three flavors of photoreceptors, can often distinguish colors as close as 1 or 2 nanometers apart.
Still, it’s hard to know exactly what a shrimp is thinking. Testing human cognition and perception is easier because we can, you know, talk to each other. Describe what we see.
With humans, the biggest barrier to empathy is that sometimes we forget to listen.