The End of Night: Searching for Natural Darkness in an Age of Artificial Light

The second major factor in our seeing well at night (or not) is adaptation, the way our eyes adapt as we move from brighter areas to darker areas. Because of the way our streetlights are usually placed, our eyes constantly have to go back and forth. “If you’re in a place that’s relatively uniformly illuminated by streetlights, then your adaptation remains fairly constant and that’s okay,” Lewis explains. “But what happens is streetlights tend to get dispersed somewhat willy-nilly and so you leave this bright spot and drive into this dark spot but you’re not adapted, and so visibility is actually worse than if you hadn’t had the streetlight there to begin with.” Lewis compares this situation to walking into a movie theater: the way it takes a few moments for your eyes to adapt. “So, as you move from lighted areas to nonlighted areas visibility can actually get worse. In many cases, an equal level of darkness is better than a sporadic light-dark, light-dark area.”

It isn’t only streetlights that cause this problem. The worst offenders, he says, are intensely lit places like gas stations and parking lots. About twenty years ago in America, gas stations began to increase the level of lighting, not for any real safety concerns but for marketing purposes. (“People like light, they’re attracted to it. There’s no question about it,” he says.) “You go in and you fill up under a canopy that was highly lit from a marketing standpoint to attract you, rather than a need for vision,” explains Lewis. “And then you drive out into a dark road and it may be a minute or two before you can readapt to the darkness, which can be very dangerous.”

“Because you might get hit?”

“Generally you’re okay,” he laughs, “you’re in the car. It’s the other folks who have to worry.”

In other words, it’s for marketing purposes (to get you to stop and buy stuff) that gas stations, shopping malls, and car dealerships are lit so brightly—not, as we might think, primarily for safety. If safety were the primary goal for these establishments, Lewis and others told me, they would be lit much more dimly so that the adaptation and glare problems would be reduced. The problem is that if one business raises its lighting level, the others will feel compelled to as well because by contrast, their establishment will seem dim and therefore less attractive—even closed.

The same scenario holds true for our society in general. As our surroundings grow brighter, we grow used to that level of brightness, and so anything dimmer seems extraordinarily dim, even dark. This is exactly what happened as artificial lighting developed through the ages. The once glorious oil lamps became dim and disgusting with the advent of wonderful gas lighting, which then became smelly and awful and unbearably dim the moment we saw electric light. In other words, once our eyes get used to seeing brighter lights, we must have brighter lights.

Roger Narboni, a lighting designer in Paris, explained this concept to me by telling of how he’d been hired to renew the lighting in a very large, very old fish market near Paris, where the business took place between 1:00 and 3:00 a.m.

“The plan was 400 lux on the fish. But when the people selling the fish saw it, they said, This is dull, we can’t see the fish. They were used to having big halogen lamps—which were hot lamps that were terrible for the fish, but they were used to them. With the new lights the atmosphere was totally different, and for them it was no good. So they said, Can you raise the level a little? And we said, Sure. And they said, Can we have double? And we said, Wow, double, okay.” He laughed. So, Narboni said, they raised the level of lighting to 800 lux, but when the fishmongers came to work they asked if the lights had even been changed. “I took out my light meter and showed them: 800 lux. And they said, Are you sure it’s working? Can we go higher? So we went to 1,200, then 1,600, 1,800, and they were never pleased. They kept saying, It’s dull, we want more. And finally I said, Okay, forget it, because we’re not going to go to 3,000 lux or 5,000 lux or to daytime. This is insane; I don’t want to do that. So I quit. And I told them, Your eyes are not able to understand what’s going on. And even if we put more, you cannot compare it, and you will ask for more and more and more, and it’s like addicts. And they never understood that.”

But a fish market in the middle of the night is one thing, I said. What about in the city itself?

“It’s the same for the urban city. If you put more lights for safety, very often and very quickly people will say, Oh, we don’t see enough, it’s not working, people are still being attacked, and we have problems and so we should put more light. And we’re going to go up and up and up. There is no limit, because the vision gets accustomed to that and we need more.”

The fascinating thing, though, Narboni said, is that this works the other way, too.

“If you go to darkness, the eye opens a lot, you get more focus, and even in a very dark environment you see very well.”

It’s a fact most of us don’t know: The human eye has an amazing ability to adapt to different lighting levels, including levels we normally think of as quite dim. While the human eye will never match those of truly nocturnal or crepuscular (active at dawn and dusk) animals, in dimly lit situations our pupil expands, our iris relaxes, and thirty times more light can enter our eye. Faced with bright lights, the pupil contracts and the iris closes down for protection. But given time to adapt to low light levels—levels that would allow the stars back into our skies and make our streets safer by eliminating glare—we actually see fairly well.

“And I try to tell the politicians, ‘Try it and you’ll see,’” Narboni explained. “In Berlin it’s like that, it’s 5 lux and everything is fine. You can see the pavement, you can see the street, and you can walk peacefully.”

Then, Narboni echoed the point made by Alan Lewis: “We are mainly driven by contrast. This is the main thing in lighting. So, if you go with a high level of light the contrast will be very poor and you won’t feel comfortable. And if you go with contrast you can feel safe even with darkness.”

Feeling safe with darkness is difficult when we have become so accustomed to high levels of light. As Bob Mizon, coordinator of the British Astronomical Association’s Campaign for Dark Skies (CfDS), explains, “We’re looking at a whole generation of people—even someone my age, and I’m sixty-plus—who have grown up with lots of lights, and who have grown up with lots of bad lights. So people now think that not only is lighting the norm, but that really glary crap lighting is the norm.”

Still, a growing number of towns and villages in the United States and Europe have been experimenting with turning off some of their lights, some of the time, in an effort to save energy—that is, to save money. And despite concern about a potential growth in crime, many of these places have experienced the opposite result. In fact, police in Bristol, England, reported a 20 percent reduction in crime, and other English towns have seen crime drop up to 50 percent since lights have been turned off after midnight. When Rockford, Illinois, decided to switch off 15 percent of its streetlights, the police chief assured the city council that no studies show correlation between lighting and crime, and that he believes lighting doesn’t directly affect crime one way or the other. In Santa Rosa, California, which has decided to remove six thousand of the city’s fifteen thousand streetlights and place an additional three thousand on a timer that shuts lights off from midnight to 5:30 a.m., the city hopes to save $400,000 a year. The bottom of the Street Light Reduction Program website reads, “Several academic studies have been published on the correlation between street lighting and crime. None of the studies make a direct correlation between increased street lighting and reduced crime. In fact some of the research indicates just the opposite.”

Other communities have had mixed success, and not because people are fearful of saving money. After Concord turned off two-thirds of its streetlights, the outcry from the populace was horrendous, Lewis tells me and the town recently voted to turn the streetlights back on, “even though most of it is pretty bad lighting.”

How does that make sense—choosing bad lighting over saving money?

“So much of it is people thinking that if there’s light it must be safer. And they don’t know what to look for, and they don’t know what good lighting is, they don’t know what bad lighting is.” (Lewis later tells me, “The nice thing about educating people about bad lighting is that there’s so many examples.”)

“And so they just think that if you turn the lighting off crime is going to go up, or I’m not going to be as safe. And none of that actually is true, in fact in many cases street lighting makes things worse not better.

“You read the letters to the editors in the local paper, and that’s what they say: You turned the lights out and now I don’t feel safe walking on the street anymore, so turn the lights back on so I feel safe. Even if, by the way,” Lewis says, “they never walk on the street.”

I’m struck by the fact that Lewis is talking about Concord, a town with a history of famous Revolutionary War violence, but with no history of pervasive violent crime. If people don’t feel safe in a place like Concord, where will they? We forget that crime tends to be concentrated in only a few places, and most places have no crime at all. This is especially true when it comes to the violent, personal crime that we tend to fear most. In Concord I found a friendly New England town, and not any place where you would expect to be attacked by a violent predator. And yet, here were glaring streetlights that did as much to impair my vision as they did to brighten my way. “They could actually reduce the lighting by about fifty percent in the downtown area,” Lewis tells me, “and still have very, very good lighting.”

Half a continent away from Concord, in the small northern town of Ashland, Wisconsin (population eight thousand), on Lake Superior’s Chequamegon Bay, you find Green Bay Packer jerseys, Day-Glo orange hunting vests, and camouflage hats or pants or jackets almost always within view, and beer and cheese served at nearly every meal. Once a town bustling with Northwoods logging and mining and railroad activity, it has only a single ore dock remaining, unused since 1965, jutting into the bay like a broken Roman aqueduct. A natural foods co-op, a bakery, and the Black Cat coffeehouse share a single block on a single street, and some residents claim you need never go anywhere else. Except, perhaps, for a late-night drive to Tetzner’s Dairy outside nearby Washburn to grab a chocolate ice cream sandwich from the freezer and leave your cash in the coffee can near the door. From the surrounding woods, on one of the nearby Apostle Islands, or better yet floating in a sailboat on the lake, the nights are still dark enough to welcome the Milky Way in brilliant detail.

But in town, light abounds. Along the lake on US Route 2 shine rows of “acorn” streetlights, the Victorian fixtures that tend to show up wherever decision makers want a nostalgic look. And in the neighborhoods you find plenty of what are, for residential and commercial buildings, the two most common sources of bright light: the “security light” and the “wallpack.”

Whether in alleys, barnyards, backyards, front yards, or driveways, the white 175-watt, dusk-to-dawn security light is ubiquitous in the United States. Drive into the country and they are often the only lights you see. I remember as a child traveling south with my parents from Minneapolis to the southern Illinois farm country where my grandparents lived. If we went at Christmas we traveled long hours after dark, and I would press my face to the backseat glass, cup my eyes, and stare at the stars. Somehow, the solitary white lights that dotted the black landscape seemed part of the romance, like bits of starry sky fallen to earth.

But that romantic view hid the reality: The fact that I could see them hundreds of yards away speaks to the glare these lights cast in all directions, including far beyond the boundaries of the property for which they were meant to provide security.

During the three years I taught at a small college in Ashland, I lived within walking distance of my office and often would take the alleyway five blocks there and back, passing right under a security light. This light was ostensibly designed to illuminate a driveway and a garage basketball hoop, and I used to imagine the swish and clank and splat of a solitary sharpshooter hitting net, rim, and puddle. But I never saw this person; I only saw, from blocks away, the light casting its shadows and glare into neighboring yards and houses. Approaching the light, I would have to shield my eyes, losing whatever dark adaptation I’d gained. I never did ask the neighbors what they thought of this light. My guess? They were so used to it they no longer noticed.

That we don’t notice glaring lights anymore has direct ramifications for light pollution, of course, but in terms of safety and security, because we are so used to bright lighting, we won’t notice if anything out of the ordinary is taking place. In fact, we won’t think to look or even want to look. And if no one is looking, lighting will do next to nothing for security.

For example, think of the many industrial warehouses spread outside every city and small town that stand unattended all weekend, every weekend. With few exceptions they will be ringed with lights, far too often wallpacks—those rectangular-shaped lighting fixtures plastered to the sides of buildings all over the country that blast horizontal light onto parking lots, plazas, courtyards … and far beyond those areas. But without a human presence—without someone watching—those lights do little more than provide illumination a criminal would need. So much so that David Crawford, founder of the International Dark-Sky Association, calls this “criminal-friendly lighting.”

The joke I heard in London is that criminals actually prefer to work in well-lighted areas because they, too, feel safer. Studies bear this out: Light allows criminals to choose their victims, locate escape routes, and see their surroundings. Asked in one study what factors deterred them from targeting a house, criminals listed “belief that house is occupied,” “presence of alarms or CCTV/camera outside the property,” and, to a lesser extent, the “apparent strength of doors/window locks.” Nowhere did they mention the presence of lighting.

“It works both ways, you see,” the CfDS’s Bob Mizon told me. “The people who claim benefits from lighting, they never put themselves in the mind of the criminal—what does he or possibly she need? What does a burglar need, what does a rapist or a mugger need? They need to assess the victim; they need to see what they’re doing. I mean, who benefits most from a big security light at three o’clock in the morning? Is it the resident fast asleep indoors, or is it the burglar sorting his tools under the light?”

Makes sense, I said, but when I look at the webpage for the police department in the suburb where my parents live, the first thing listed under preventative measures a homeowner can take: “Home is illuminated with Exterior Lights.”

The police in his town offer the same message, Mizon explained: “You must have lights to prevent crime. And when asked about the source of this information, the data, they haven’t got any. They just assume it’s true. The police are mired in the same degree of ignorance as society.”

This doesn’t mean that the Campaign for Dark Skies is against artificial light.

“It’s not as though we want people stumbling about in medieval darkness,” Mizon said, smiling. “I mean we don’t campaign for no lights. That’s crazy. If people want lights they should have them. It’s a democracy; people fought and died for it. Let’s say everybody in the village votes for street lighting. Great, they must have it. But it’s got to be the right stuff. And that’s what many people don’t realize, that there’s lighting, and then there’s lighting.”

Helping people understand this is a large part of Mizon’s job.

“I say to them, look, there are thousands of little villages in England with no streetlights—are they hot spots of crime? No, they are not. And when you see crime on the television or you see people rioting in city centers or fighting each other on the CCTV cameras and vomiting in the gutters, are those dark places? No, they’re brightly lit places. They’re the brightest places in Britain, and they are the most crime-ridden places in Britain. So what’s the conclusion? Does light prevent crime? Of course not, it’s rubbish.”

Overall, the available studies and statistics back Mizon’s claim, and echo what several people told me, that the term “security lighting” is simply oxymoronic because it assumes a link between security and lighting that research does not support.

In 1977, a U.S. Department of Justice report found that “there is no statistically significant evidence that street lighting impacts the level of crime.” In 1997, a U.S. National Institute of Justice report concluded, “We may speculate that lighting is effective in some places, ineffective in others, and counterproductive in others.” In 2000, the city of Chicago performed a study in which an attempt was made to “reduce crime through improved street and alley lighting.” The city found that “there did not appear to be a suppression effect on crime as a result of increased alley lighting.” In 2002, Australian astronomer Barry Clark conducted an exhaustive review of the research available and concluded that there is “no compelling evidence” that lighting reduces crime and, in fact, “good evidence that darkness reduces crime.”

How shielding our lights cuts out glare and improves our vision (notice the “bad guy” standing in the open gate). (George Fleenor)

In late 2008, the Pacific Gas and Electric Company (PG&E) was required by California law to find ways to reduce energy expenditures. In an effort to look into how the reduction of street lighting might do so, company representatives asked for and received an independent review of existing research “relating to any relationship between night-time outdoor lighting and security.” The review found no research that presented “sufficient evidence to demonstrate a causal link between night-time lighting and crime” and concluded: “the available results show a mixed picture of positive and negative effects of lighting on crime, most of which are not statistically significant. This suggests either that there is no link between lighting and crime, or that any link is too subtle or complex to have been evident in the data, given the limited size of the studies undertaken.”

As Barry Clark argued in 2002, “Where the justification includes or implies crime prevention,” lighting costs “appear to be a waste of public and private funds.” Updating his review in 2011, he reiterated his earlier findings and wrote, “Given the invalidity of evidence for a beneficial effect and the clear evidence to the contrary, advocating lighting for crime prevention is like advocating use of a flammable liquid to try to put out a fire.”

These studies have had little effect, however, on the perception that lighting reduces crime at night, and that more light reduces crime further. Perhaps that’s because most of us have never heard of these studies, and so continue to assume a connection between darkness and crime, lighting and security. It doesn’t help that a handful of studies directly or indirectly sponsored by the lighting industry or utility companies persist in claiming that lighting deters crime despite mounting evidence to the contrary. By selling more lights or selling more energy, these companies stand to gain the most wherever the lights are brightest. Widespread ignorance reinforced by questionable research has much to do with this, no doubt.

But there’s something else going on here, too. You get the feeling someone who says “Then send your wife and kids into the darkness and see what happens, or ask a rape victim what they think” isn’t going to be dissuaded by Clark’s study or any other study. Dare to question the idea that we need lots and lots of bright lights for safety and, as Martin Morgan-Taylor of the Campaign for Dark Skies told me in London, “It will often raise quite an aggressive response from people, because it really is the fear of the dark, isn’t it?”

“This most ancient of human anxieties,” explains historian Roger Ekirch, “has existed from time immemorial … Night was man’s first necessary evil, our oldest and most haunting terror.” The reasons—rational, even—that we have feared the dark of night are many: threats from wild animals, attacks from robbers or highwaymen, deadly terrain, and especially fire. Add to those reasons our propensity for irrational fears such as ghosts, witches, werewolves, and vampires and we had plenty of reason to fear the dark. Regardless of which came first—the rational or irrational—as we evolved, those fears were kept intense by the human eye’s limited ability in the dark and our imagination’s vivid ability to see night’s demons all too well. Christianity, which saw Christ as “light eternal” and Satan as Prince of Darkness, further ingrained this view of the world. In the eyes of the church, continues Ekirch, “the devil embraced darkness, literally as well as metaphorically. Night alone magnified his powers and emboldened his spirit. Indeed, darkness had become Satan’s unholy realm on earth.”

But most of us no longer fear attack by wild animals, deadly terrain, or fire at night; nor do we recall our last encounter with a highwayman. And while we love them in movies, we don’t normally fear meeting witches, ghosts, or werewolves in the dark—or at least, we don’t admit we do.

No, now we fear each other.

Three miles northwest of downtown Winston-Salem, North Carolina, the campus of Wake Forest University, a highly ranked school that is home to more than seven thousand students, lies embraced by quiet residential neighborhoods or estates on all sides. This is where I work, where I experience night’s darkness on a regular basis—leaving my office on a winter’s early evening, returning after dinner to hear a visiting speaker, walking with Luna. A leafy tree canopy made of magnolias and maples, dogwood and pines, covers walkways and streets and pedestrian squares, the brick buildings made in the Georgian style. Wait Chapel rises at the north end of the main quad, spotlights on its steeple, while other lighting includes both the old and the new: security lights and wallpacks and cobraheads, but also fully shielded streetlights, “dark sky–friendly” acorns, and other attractive Victorian fixtures. A recently commissioned report on campus lighting states as a goal to “continue the intimate feel of campus.”

“And that means a balance of darkness and light,” says Jim Alty, vice president for facilities. “If you want to be out with your girlfriend, or if you want to talk with a colleague or classmate, you don’t want to be in a brightly lit space that’s making you squint. So our idea is to offer pathways that are well-lit but, once you get away from the pathways, not trying to make it look like Times Square.”