Ask a Neuroscientist · Sources

Why does the same evening lamp affect some people far more than others? Melatonin and a 50-fold range

Ask a Neuroscientist · posted October 29, 2026

The studies, records and images behind this post, each linked to the original. Where a slide shows a number card, the number is quoted from the study named on the card.

Education, not medical advice.

Research cited

  1. Phillips AJK, Vidafar P, Burns AC, McGlashan EM, Anderson C, Rajaratnam SMW, Lockley SW, Cain SW (2019), High sensitivity and interindividual variability in the response of the human circadian system to evening light, PNAS 116(24):12019-12024, doi 10.1073/pnas.1901824116 (full text read Oct 17, 2026, Europe PMC PMC6575863, CC BY-NC-ND, figures not reused; PubMed 31138694) doi.org

Images, slide by slide

Slide 1
Archer and Warner, Astral Lamp, Brass and glass, ca. 1855, 68.111.1 (The Metropolitan Museum of Art)Archer and Warner, The Metropolitan Museum of Art (public domain)Museum or journal record
Slide 2
Unknown maker, Candle Bracket, Wrought iron, 15th century, 47.101.79 (The Metropolitan Museum of Art)Candle Bracket, The Metropolitan Museum of Art (public domain)Museum or journal record
Slide 3
James McNeill Whistler, Reading by Lamplight, etching and drypoint, 1859, 1998.396 (Cleveland Museum of Art)James McNeill Whistler, The Cleveland Museum of Art (CC0)Museum or journal record
Slide 4
Number card made for this post, citing Phillips et al. (2019), PNAS.The study
Slide 5
Chart drawn to scale for this post from Phillips et al. (2019), PNAS 116(24):12019-12024: evening light of 10, 30 and 50 lux delayed the apparent melatonin onset by 22, 77 and 109 minutes compared with dim light under 1 luxPhillips et al. (2019), PNAS 116(24):12019-12024, chart drawn for this postMuseum or journal record
Slide 6
Number card made for this post, citing Phillips et al. (2019), PNAS.The study
Slide 7
Chart drawn to scale for this post from Phillips et al. (2019), PNAS 116(24):12019-12024: 6 lux versus 350 lux, drawn on a linear scale to show the more than 50-fold differencePhillips et al. (2019), PNAS 116(24):12019-12024, chart drawn for this postMuseum or journal record
Slide 8
Unknown maker, Lamp, 1847, BK-NM-11177-143 (Rijksmuseum, Amsterdam)Lamp, Rijksmuseum, Amsterdam (public domain)Museum or journal record
Slide 9
Joseph Lownes, Candle Holder, Silver and steel, 1790 to 1810, 24.109.38a to c (The Metropolitan Museum of Art)Joseph Lownes, The Metropolitan Museum of Art (public domain)Museum or journal record
Story 1
Unknown maker, Lantern for a Lamp, Earthenware and carved decoration and unglazed, 9th to 10th century, 39.40.87 (The Metropolitan Museum of Art)Lantern for a Lamp, The Metropolitan Museum of Art (public domain)Museum or journal record
Story 2
Illustration made for this post (labelled Illustration; not data) from Phillips et al. (2019), PNAS 116(24):12019-12024: about 25 lux halved melatonin on average, a level at or below typical indoor lightingPhillips et al. (2019), PNAS 116(24):12019-12024, illustration drawn for this postMuseum or journal record
Story 3
Matthew Boulton, Twelve-light candelabrum, Silver, 1805/6, 60.55.9a to ee (The Metropolitan Museum of Art)Matthew Boulton, The Metropolitan Museum of Art (public domain)Museum or journal record

Follow Ask a Neuroscientist

I'm taking on clients for storytelling strategy and content production and operations. DMs are open.