Where Light Slows Down: The Hidden Power of Transitional Illumination

There is a kind of magic in the in-between. The moments when the sun dips just below the horizon, when a single candle flickers in an otherwise dark room, or when a streetlamp casts an amber glow across wet pavement. These instances of liminal lighting, neither fully dark nor fully illuminated, carry an emotional weight, a sense of nostalgia, quietude, or even transcendence. But this isn’t just poetic; neuroscience is beginning to uncover the biological and psychological mechanisms behind why these states of light affect us so deeply.

This blog delves into the science behind twilight, candlelight, and streetlamp glow, showing how they trigger specific responses in the brain and body, and how designers can harness these effects to create spaces that evoke memory, calm, and reflection.

The Biology of Liminal Light: How Our Eyes and Brains Process Transitions

Human visual perception evolved to adapt to the changing light of the natural world. Unlike the binary on/off of artificial lighting, natural light changes gradually, often dramatically, throughout the day. During twilight, the eye enters what’s known as the mesopic range, a transitional phase between photopic vision (daylight, cone-dominated) and scotopic vision (nighttime, rod-dominated). In this liminal state, both rods and cones are active.

This has several effects:

• Reduced visual acuity and color discrimination: The world appears softer and less defined, encouraging slower movement and reflective behavior.

• Heightened motion sensitivity: Rods are excellent at detecting movement, and in low light, we become more alert to shifting shadows and silhouettes.

• Neurophysiological alerting: The transition between cone and rod dominance triggers brain regions responsible for adaptation, particularly the superior colliculus and pulvinar nucleus, which link visual input with arousal and attention.

These subtle shifts in light and perception can create emotional responses, what researchers in affective neuroscience call bottom-up emotional priming. The environment affects how we feel before we even realize it consciously.

Twilight as a Circadian and Emotional Trigger

As natural daylight fades, the retina detects a reduction in short-wavelength (blue) light, signaling the suprachiasmatic nucleus (SCN) in the hypothalamus that evening is approaching. This master circadian clock initiates melatonin production via the pineal gland. Melatonin is more than just a sleep hormone; it’s a neural modulator involved in reducing cortisol, relaxing the nervous system, and helping the body shift from alertness to rest.

Twilight, therefore, is not just beautiful; it’s biologically meaningful. It’s a shift point, a neuroendocrine cue that tells the body it’s time to slow down. In this way, twilight is emotionally primed; it helps reduce sympathetic nervous system activation and encourages parasympathetic processes like digestion, healing, and emotional processing.

Functional MRI studies have shown that liminal light conditions can activate the default mode network (DMN), a set of brain regions associated with introspection, memory recall, and self-referential thinking. This is why dusk often feels nostalgic or reflective: it literally turns down the sensory volume and turns up internal narrative processing.

The Evolutionary Comfort of Candlelight and Firelight

For tens of thousands of years, humans gathered around fire after dark. That glow is embedded in our evolutionary memory. The flicker of flame operates within the low-luminance, warm color temperature spectrum (typically 1500K–1800K), which strongly activates melanopsin-insensitive pathways, meaning it doesn’t suppress melatonin like bright white or blue light does.

Fascinatingly, research published in Evolutionary Psychology suggests that firelight lowers blood pressure and encourages prosocial behavior. A study by Lynn et al. (2014) found that participants who watched fire (with sound) experienced greater relaxation and increased altruism. The researchers hypothesized that fire’s flicker mimics biophilic patterns, what is now referred to in design psychology as biophilic complexity, or non-threatening visual variability that soothes the nervous system.

Moreover, the flickering pattern of fire stimulates brainwave states associated with theta waves (4–8 Hz), linked to meditative, drowsy, and creative mental states. This is the same brainwave activity found during deep daydreaming and early sleep stages. Candlelight, then, is not just ambient, it’s neurologically calming, even hypnotic.

Streetlamps, Sodium Light, and Nocturnal Nostalgia

Streetlamps, particularly those that emit warm, amber hues like low-pressure sodium (LPS) or high-pressure sodium (HPS) lamps, carry with them a kind of romantic melancholy. From a lighting design perspective, these lamps emit very narrow or limited spectral distributions, mostly in the orange-red wavelengths (~589 nm), which also do not strongly suppress melatonin. As a result, they support circadian rhythm maintenance better than blue-rich LEDs.

But their effect is more than physiological. The aesthetic of sodium lights - grainy, soft-edged, with halo effects and low contrast - triggers retroactive memory formation. That is, they create perceptual conditions under which memories are more likely to be encoded with emotional valence. The hippocampus (the brain’s memory center) is especially responsive to emotionally charged or context-rich environments, and dim, mood-heavy lighting plays into that.

Architectural theorist Juhani Pallasmaa has noted that streetlamps offer a rare form of “visual silence,” allowing the eyes to rest and the imagination to take over. This aligns with the theory of affective atmospheres, which suggests that environments generate feelings that precede cognition. Streetlamp-lit environments feel liminal, emotionally charged, and reflective precisely because they cue the brain to slow down and fill in the gaps.

Memory, Light, and the Emotional Brain

Memory and emotion are inseparable. Neuroscientist Joseph LeDoux famously showed that the amygdala, which processes fear and pleasure, enhances the consolidation of emotionally significant memories in the hippocampus. Liminal lighting plays a unique role here. Because of its quiet, slowed-down, and emotionally suggestive nature, it fosters what memory researchers call deep encoding, the process by which information is linked to context, emotion, and significance.

When you walk alone under a streetlamp or sit in candlelight, your brain may more richly encode those moments because they feel important. It’s why many of our most vivid memories take place not in bright daylight, but during dusk, evening, or firelight. The lighting acts as a mnemonic device, a soft anchor for recalling events long after they’ve passed.

From a design standpoint, this means lighting can influence not just how a space feels in the moment, but how it is remembered. The lighting conditions during a life event can become emotionally sticky, strengthening attachment to place, person, or emotion.

Liminal Lighting in Design: Evoking Stillness, Transition, and Belonging

So, how do designers leverage this? Modern lighting systems prioritize uniformity, brightness, and efficiency, often at the cost of psychological richness. But we are now learning that transitional lighting states can be intentionally used in spaces of healing, contemplation, or emotional resonance.

Consider the following strategies:

1. Lighting as a Transition Marker

Use dim-to-warm LEDs or indirect lighting to mark thresholds, such as the entrance to a chapel, a waiting room in a hospital, or a quiet nook in a library. This echoes the body’s circadian adaptation and supports psychological transitions between activity and stillness.

2. Activate the Default Mode Network

In areas intended for reflection, museums, memorials, counseling spaces, use soft, warm, low-glare lighting. Studies suggest the DMN becomes more active when sensory input is muted, allowing deeper self-processing and memory integration.

3. Design for Evening Memory Formation

In hospitality or wellness design, mimic the warmth and movement of candlelight or firelight. Low flicker rates in LED candles or smart fireplaces can trigger biophilic responses and deepen emotional memory of the space.

4. Streetlamp-Inspired Lighting

Use amber-hued exterior lighting for urban placemaking. Cities are rapidly replacing sodium lights with bright white LEDs, which disrupt melatonin and flatten the emotional atmosphere. Instead, streetlamp-inspired fixtures can foster calm, narrative richness, and place identity.

Liminal Light and Trauma Recovery: A Healing Modality?

There’s growing interest in how lighting can play a role in trauma-informed design. People who have experienced trauma often have hypervigilant nervous systems. Bright, unpredictable lighting can exacerbate this. Liminal lighting, with its consistency, softness, and biophilic flicker, may help calm the amygdala and support neuroception of safety, a term coined by Dr. Stephen Porges in his Polyvagal Theory.

In therapeutic spaces, this could mean:

• Using adjustable warm lighting during therapy sessions.

• Incorporating candles or fireplace visuals in mental health retreats.

• Designing transition rooms with indirect, twilight-like lighting before entering more stimulating areas.

This is especially relevant in environments like pediatric hospitals, women’s shelters, or spaces for neurodivergent individuals, where lighting can either regulate or dysregulate the nervous system.

Designing for the Liminal Mind

Ultimately, liminal lighting is about embracing the thresholds of perception. In a world of constant stimulation, it offers something rare: the capacity to pause. These lighting states do not command attention, they invite presence. They ask us to slow down, to reflect, and to feel.

Designing with liminal light is not simply about aesthetics, it is about crafting a temporal experience that honors the human nervous system. It means moving away from the harsh binary of light and dark, and instead embracing the soft ambiguity in between. That ambiguity is where memory takes root, where emotion softens, and where meaning often emerges.

In architectural terms, liminal lighting is slow lighting. It echoes the pace of breath, of dusk, of fire. It is not the spotlight, but the glow around the edge of things.

Closing Thoughts

We often think of lighting as functional, a tool to see, to work, to navigate. But it is also emotional, neurological, and profoundly human. Twilight, candlelight, and the glow of streetlamps are not simply romantic notions; they are evolutionarily embedded experiences that signal safety, rest, storytelling, and memory.

As neuroscience continues to illuminate how our brains respond to the in-between, designers are uniquely positioned to bring those findings into the built environment. Through careful calibration of color temperature, flicker, intensity, and transition, we can design spaces that feel not only beautiful but meaningful, spaces that live on in the body long after we’ve left them. Because in the end, it is often not the brightest lights that we remember, but the ones that glowed quietly when everything else was fading.