Full-text audio version of this essay.

This essay is part of Home Icons, a series about the cultural and material histories of domestic objects. Read the others here.

When I first moved to the UK from Sydney eight years ago, I bought a SAD lamp on the recommendation of a friend who, seeing me traumatized by my first experience of a British winter, “diagnosed” me without hesitation. SAD, or Seasonal Affective Disorder, is a mood disorder that resembles “regular” depression but coincides with the winter months. SAD lamps exude a bright glow which imitates the full-spectrum (white) light of the sun, said to trigger the production of serotonin and re-set our circadian rhythm, the process that regulates our cycle of sleeping and waking. Circadian rhythms are endogenous (“built in”), but are subject to external factors known as “zeitgebers” (in German, literally: time-givers). Bright light is one such time-giver, and can recalibrate the programmable “body clock” to a desired schedule.

SAD lamps are available in many shapes and forms, but two main forms dominate. The first aims at maximum surface area (a common shape is a flat sheet of light known as a “lightbox”), which one sits in front of to receive the daily recommended “dosage” of 30 minutes exposure per day. The second, more recent, and perhaps more popular iteration is a “wake-up light,” a softer, rounder model which simulates the experience of dawn, building to its full glow over a programmable 30-minute period at the start of the day. SAD lamps are certified medical devices, with prices that range from about $40 to $250; mine, the Lumie desk lamp, is a more compact version of the lightbox, with a flexible neck designed specifically for individual desk work. It cost me an extortionate £120.

These days, the home is made to carry an enormous amount of responsibility

In the eight years since I bought my SAD lamp, I have hardly used it; I persisted in lugging it with me from home to home due to its embodied monetary value alone. During lockdown, with my exposure to any kind of daylight at an all-time low, I decided to give it a proper shot. These days, the home is made to carry an enormous amount of responsibility: It must be a space of rest, a space of work, a space of treatment and convalescence, a space of both safety and stimulation. Within this zone of painfully undifferentiated time, the impulse to curate ideal, private domestic spheres conducive to deeper sleep and more productive days grows stronger. Products that position themselves as helping us navigate the “natural” shifts in our energy levels are attractive, because they also promise a simulation of “normal life”: structure, balance, and a sense of rhythmic synchronicity.

My SAD lamp cranes over my desk, blasting me with lumens while I work or browse the internet. In many ways this is typical of the many new habits I’ve adopted over the course of this year in the name of health — exercise videos, vitamin D, a daily cup of drinkable yogurt — but the lamp’s role is more ambiguous. I get the feeling that it’s working on me, tuning me somehow; but it’s not entirely clear how, or for what end. It sits uneasily on my desk beside a plant, a radio, and a decorative vase, looking conspicuously medical.

SAD lamps have been couched by specialist lighting companies in the language of trickery and artifice (fake dawns and imitation sunlight). This idea of “tricking” (or “hacking”) the brain is a trope of pop science, as if “human nature” were a plodding, stable, predictable motor that could be outwitted by technology. Since its adoption in popular parlance, the idea of the circadian rhythm has provided a neat way to understand the complexity of our needs and their fluctuations throughout the day; it also provides some hope of altering these cycles for optimal functioning. The SAD lamp, it can be argued, works to calibrate one’s body out of mammalian “winter hibernation mode” and towards the machinic rhythm of workers under neoliberal capitalism. But then we get into murky territory: what is the “natural” body anyway?

The term Seasonal Affective Disorder was coined in the early 1980s by the South African psychiatrist Norman Rosenthal, who was reportedly driven by the desire to uncover the source of his own recurrent feelings of lowness and lethargy during the winter months in the northeastern United States. Rosenthal, a self-described “healer” and proponent of transcendental meditation, went on to study the effects of the seasons on human psychology more widely, including the psycho-physiological effects of “spring fever,” which he would later describe in his blog as “a feeling that seizes you with its urgency and impulses, driving you to pursue the object of your desires” (a kind of horny, giddy productivity that is the mirror image of SAD).

The idea of the body operating according to a daily cycle is not new, and is present in many medical traditions, including traditional Chinese medicine, according to which every organ reaches its peak functioning at a particular time of day. The research behind SAD lamps in particular belongs to the broader field of chronobiology, which examines periodic and cyclical timing processes (such as solar, lunar and seasonal rhythms) in relation to living organisms. While the effect of light on other creatures has long been a well-established fact, up until the ’80s, Western scientific institutions failed to recognize that light affected human beings in the same way. Recently, the health-giving effects of sunlight exposure have become news again, with studies linking increased Vitamin D levels to faster recovery rates from Covid-19, and with UV-light shown to minimize the spread of airborne droplets.

Sunlight is also thought to have positive effects on mood, likely due to a combination of factors, of which the interplay is not completely understood. The light emitted by SAD lamps — though it may resemble sunlight — does not emit UV radiation, and thus does not encourage the production of Vitamin D. The device operates on the assumption that sunlight’s effects on mood and on the body can be simulated by very bright, white light, which stimulates the production of serotonin and regulates the release of melatonin when it hits the retina at the back of the eye. SAD lamps evolved out of other forms of phototherapy (such as those used to treat skin infections), but in their current form they seem to be developed primarily by consumer brands.

The circadian rhythm has provided a neat way to understand the complexity of our needs and their fluctuations throughout the day

Dominating the SAD lamp market is the UK-based company Lumie, the makers of my own lamp — one of the first distributors of SAD lamps and inventors of the “wake-up light.” Lumie insists that all its products are research-based; and while they are certified under the European Medical Devices Directive , there doesn’t seem to be a straightforward answer as to whether they actually work to treat SAD. Here in the UK, the National Health Service (NHS) website says that the lamps are “popular” but their effectiveness is unclear, and recommends that sufferers pursue the same treatments used for regular depression. But the NHS also commissioned 21 custom-built Lightboxes from Lumie for use in an ICU ward in Bristol. Research by UK policy institute Cochrane found that evidence for light therapy’s effectiveness for SAD is insufficient, though it also found that use for the treatment of non-seasonal (regular) depression was “modest but promising.”

The use of SAD lamps, then, seems to be partly experimental. Their popularity is linked to the popularity of the concept of SAD itself — which, in positing itself as a disruption of a natural balance, hints at the existence of a perfect synchronicity between body and nature; a synchronicity that — once understood — could be tweaked, tuned and adjusted according to the relationship that we want to have with earth systems.

The coinage of Seasonal Affective Disorder coincided with the rise of “personalized” medicine and “precision” medicine in the 1980s, which largely had to do with an understanding of genomics as playing a role in the way patients would respond to specific treatments (especially in cancer treatments). It coincided, too, with the rise of “holistic” medicine (encompassing alternative medical practices popularized during the ’60s and ’70s), which considers lifestyle, mood and environment as factors in a patient’s health. This language — “holistic,” “precision,” personalized” — has since been taken up and recontextualized by companies that profit from the shift to increasingly privatized medical systems. They appeal to a sense of consumer individualism, while also invoking the idea that we belong to wider environmental patterns.

Much of what we know about circadian rhythms has its origins in military research — specifically, the never-ending military quest for effective “sleep reduction.” Such research has been driven by the desire to overcome, rather than to understand, our need for rest. A 2019 report in the journal Neurospsychopharmacology, sponsored by the Military Operational Medicine Research Progamme, finds that “for military personnel, timed light ‘recipes’ can be a solution for phase-shifting sleep/wake cycles for the purpose of ‘owning the night,’ and executing a successful night mission that maximizes performance and reduces risk for injury.” This history partly explains the emphasis, in discussions of the circadian rhythm, on calibration and manipulation, with the underlying idea that nature, once known, can be bent to our will. The notion of a timed light “recipe” is typical of “circadian health” gadgetry (such as blue light dimmers, temperature-regulating pillows and sleep-tracking headphones), which encourage “precision” — as opposed to the loosely equivalent idea of “balance” — suggesting that our relationship to wider cycles is subject to a more scientized complexity that must be navigated by technological means.

Fittingly, the SAD lamp comes with a precise dosage for improving mood and concentration: 30 minutes. When I forget to turn off the lamp and sit too long in front of it, which happens often, I feel weird, like I’m being adjusted in ways I don’t fully understand. The lamp pitches my (inferior) “mammalian brain” against my (superior) “human brain,” making my body the site of a war waged through deception. Ironically, I suspect that the reason I bought the lamp at all has less to do with its post-humanist ambitions, and more to do with its suggestion that I have a “mammalian brain” at all.

Increasingly, I have grown to feel deeply ambivalent about my SAD lamp. It has a long, grey spine, and an unnerving rectangular plate for a face, and it emits a light that I associate strongly with my childhood dental practice, perpetrators of a botched root canal that I suffered through when I was 16. It’s impossible to deny that it helps me focus; although perhaps that’s only because the experience of sitting in front of it is so intensely unrelaxing. It could (perhaps generously) be compared to the feeling of getting into a scalding bath, or a freezing cold shower.

There’s a reason that metaphors of illumination and liquidity overlap so much (one often talks of being “bathed in light”). They share not only the capacity to immerse or irradiate a body, but also the capacity to cleanse and purify it. In Europe, heliotherapy — the use of the sun’s light for healing — was a key element of 19th century sanatoria, being thought essential for recovery from tuberculosis. As this article argues, a common European dictum for hygiene in the 19th century was “light and air” (licht und luft), which later became central for the practices of modernist architects such as Le Corbusier, enshrining the blueprint of the sanatorium in the idea of what a home should be.

There is logic to this approach: sunlight can kill bacteria, especially the kind that breeds in dark, dusty homes. But when it comes to the role of artificial light within the home, the notion of light as “healthy” is perhaps more symbolic than functional. We often associate poor mental and physical health with an absence of light: illnesses of the flesh show up first as an inverted shadow on the X-ray, and depression, too, is figured as a darkness, one that moves like bacteria, feeding off organic matter. The home lighting industry has always been bound up with the desire to create atmospheres that are conducive to domestic wellbeing: it is possible to imagine that “good lighting” might have a role to play in chasing away “dark thoughts.” Whereas this effect was once largely thought of as atmospheric, with the SAD lamp, the role of light in the home has become more explicitly medicalized. And the straightforward dictum of licht und luft has been replaced by an approach that emphasizes the light right at the light time — a personalized “light recipe” that could tune one’s inherent, biological synchronicity with external rhythms for an ideal daily rhythm, one that maximizes productivity during the working day, and then maximizes rest at night.

I suspect that the reason I bought the lamp at all has less to do with its post-humanist ambitions than its suggestion that I have a “mammalian brain” at all

The importance of “precision” here springs from the fact that light is increasingly thought of as a contaminant (the term “light pollution” refers to excess artificial light at night). Currently there is a minor health panic around blue light in particular, which is emitted in high quantities by bright, white-colored LEDs, and essentially works on the body in the same way the SAD lamp does, modifying our circadian rhythms and causing the delayed production of melatonin. When we are exposed to too much blue light late in the day, this can lead to disrupted sleep patterns, cardiovascular problems, and even some forms of cancer. Shift workers are most susceptible to these effects: in 2009 the Danish government made the landmark decision to offer compensation for shift workers suffering from breast cancer. Discussions of the health effects of light, though, tend to side-line shift work, focusing instead primarily on the omnipresence of screens, which have a higher concentration of blue light than other wavelengths. In this context, the threat of blue light is likely exaggerated — at least compared to the mental and physical health effects of overworking, social media use, information overload (all the things we actually do with screens).

In response to the “blue light problem,” a wave of software has emerged which aims to lower the blue light emissions of our screens at night, thus minimizing the adverse effects of late-night exposure. The most precise of these is the freeware f.lux, developed by Michael and Lorna Herf, who both previously worked for Google developing the photo-organizing and editing tool Picasa (now Google Photos). Lorna, a painter, had color-changing lightbulbs fitted in the house to mimic the fluctuations of ordinary daylight and allow her to paint into the night, but found the presence of bluish electric screens ruined the balance. Allegedly, this inspired her and Michael to create f.lux, which uses inputted location data to initiate a virtual sunset in tandem with the setting of the actual sun, warming the screen gradually to a deep orange. According to f.lux, we are more connected with natural cycles if the colors of our screens reflect the cyclical quality of sunlight.

The f.lux website is intentionally lo-fi, and has an open-source feel about it, despite the fact that it is copyrighted to F.lux Software LLC. One of the main features is the “forum,” which is full of in-depth discussions of the intricacies of adjusting artificial lighting in relation to circadian rhythms. The intense precision with which the forum approaches the topic of blue light is characteristic of discussions of “sleep hygiene,” a term that gained prominence in the 1970s, referring to a somewhat foggy area of research that is crowded by technological solutionism. The idea of sleep hygiene appeals to a collective sense of the erosion of rest — something that Jonathan Crary has written about extensively — while also suggesting that the failure lies not with systemic problems, but with individuals whose practices and habits are not conducive to sleep.

In a paper from 2018, researcher Dylan Mulvin writes about f.lux and other “Night Modes” in relation to media prophylactics — which he defines as “the techniques, technologies and design choices that are made on behalf of or by users to pre-empt the ill effects (whether imagined or concrete) of media use.” These fulfill an intermediary function in an imagination where “humans possess a natural and biologically compatible relationship to the sun that is in conflict with an artificial but socially necessary relationship to lit and lighting technologies.” Like the recommendation of blue-light blocking glasses for shift workers, Mulvin argues that Night Modes individualize responsibility for the bodily and mental harm that results from the use of screens at late hours, while remaining nonpartisan about the reasons many people face increased exhaustion. The difference between being well-rested and under-slept is, more often than not, a matter of privilege — a truth that is somewhat flattened by discussions of the circadian rhythm.

Given that they are essentially two iterations of the same phenomenon, the choice to differentiate between the harmful blue light of the screen and the beneficial white light of the SAD lamp becomes a way to resolve the paradoxical status of light as something both natural and unnatural, necessary and polluting. “Blue light” connotes phantoms, the supernatural, the online realm and the spiritually impure, while “white light” suggests health, cleanliness, and even spiritual purity. The more tangled our relationship with light, the larger the market for expensive consumer technologies, which — couched in scientized, medicalized language that simultaneously employs and obscures the deep-rooted symbolic associations at play — promise to mediate our relationship to natural earth systems.

SAD lamps tap into our desire to believe in ourselves as part of wider ecologies, but they also position consumer goods as necessary mediators of this relationship, and the individual home as the site of this mediation. They don’t just sell us a solution for disrupted circadian rhythms; they also sell us the problem — the notion that as human beings we are still part of wider rhythms, patterns and processes that affect our bodies intimately. They reassure us of our own untainted animality or “naturalness”; of the fact that like bees, birds, plants and insects, we too are sensitive to light. This prospect is even more attractive in the face of a global threat that has clouded many people’s sense of belonging to the wider world. (This is perhaps also why “cottagecore” — an internet-based aesthetic that advertises a pastoral ideal of humans living in perfect co-dependence and synchronicity with the land — has become so popular this year.)

Likewise, a depression that arises in response to “natural” seasonal patterns is less of a menacing prospect than a depression that arises in response to unpredictable combinations of multiple biological and social factors. Recognizing SAD as a syndrome, it is still true that quantity of light is not the only difference between our experience of summer and winter: some of the more important factors are cultural and societal, shifting according to context. The technologies surrounding SAD are unique among treatment options for mental health disorders in that they explicitly locate the cause, or at least stimulus, in the external (natural seasonal changes), but this doesn’t prevent them from shrinking the solution down to the individual patient. In other words, the SAD lamp promotes an idea of humans as biological organisms responsive to the wider (“natural”) environment, but bypasses social, economic and political factors altogether.

As healthcare is increasingly privatized, a minority of patients have access to more highly personalized diagnoses and treatments, while public health systems and other public services that intersect with health (such as housing and benefits) have suffered large budget cuts. The devastating impact of pandemic itself is, in part, a result of this shift in perspective and cuts to funding. In the UK this winter, a new strain of coronavirus has been detected and we are facing a renewed national lockdown until spring. With minimal government intervention in the effects of the resulting economic recession, levels of poverty, unemployment and homelessness are skyrocketing. Meanwhile, people with severe mental health crises compete for ward-space with Covid-19 patients, and the waiting list for psychiatric evaluations continues to grow.

In the face of all this, the idea of curing depression with artificial sunlight begins to seem absurd, and, to me, speaks eerily of a trope of the (underground) apocalypse bunker: the home-as-total-world, fortified against external devastation. Nevertheless, I will probably continue to blast myself with 1000-watt light on a daily basis over the coming months, if only for the routine it offers, and for the feeling, however shallow, that I am just a biological organism after all. At a point where I am moving through my days with the uneasy feeling of growing untethered to the world, beholden to my own small domestic island, it is comforting to imagine that some part of me remains moved by rhythms beyond the walls.