We don’t take pleasure in eating food that’s still searingly hot from the oven, even though that delivers exactly the same sensation we get from chillies: same receptors, same nerves. We don’t choose to chemically burn our tongues with strong acids. So why do we happily, even eagerly, inflict pain by chillies? Whatever the secret is, it seems to be unique to humans. No other mammal on the planet has a similar taste for chillies.
Bob Holmes in The Guardian.