(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.)

(THE CONVERSATION) A new scientific study shows that bright electric light exposure of preschool children in the evening suppresses melatonin production almost completely, an important addition to the growing body of research in this area. Melatonin suppression is a marker of disruption of our circadian rhythms.

Ten kids, ages 3 to 5, were exposed to bright light (~1000 lux from a light box) for one hour before their habitual bedtime, about 8 p.m. Melatonin suppression (where the b...