Over 300 million years ago, a minnow-sized fish died and fell to the bottom of a prehistoric swamp near the village of Trawden, Lancashire, in northwest England. The remains of this tiny fish—known as ...

Picture a mouse taking rapid, staccato sniffs of a crumb it's found while foraging for food. Now compare that with a human leaning in for a single, deep inhale to gauge whether a cantaloupe is ripe.

Line up the brains of a fish, bird and a mammal, and something unexpected comes up. You do not see three different answers to the problem of making sense of the world. You see one answer, tilted three ...