Remember “the dress”? The black and blue—or was it white and gold?—phenomenon catapulted across the internet 2 years ago when people saw different colors in the same picture. Now, one psychologist writing in Slate has a new idea about what went down. In an online survey of some 13,000 people published in the Journal of Vision, he found a subtle link between what colors they saw and whether they identified as a “morning lark” or a “night owl.” Self-identifying larks are more likely to perceive the dress as lit by natural light and colored white and gold. Night owls are more likely to assume the dress is shrouded in artificial incandescent light, making it appear black and blue. But the correlation is far from perfect, says the scientist, something this author can attest to.