I Tried to Make Twinkle Twinkle Terrifying

You've sung it a thousand times, probably to someone who was trying to fall asleep. C, C, G, G. It's the safest melody most of us know. So this week we ran an experiment: take that exact tune and push it, one change at a time, until it sounds like the opening of a horror film. Each change has a reason behind it, and one of them flickers inside the range that, in one study, people found hardest to bear. Watch with headphones if you can, and maybe not right before bed.

The part worth keeping: a lot of that fear came from two intervals, the tritone and a half step held close together, and your ear can learn to name both. Intervalis on ToneGym plays two notes at once and asks you for the distance.