A few years ago I climbed over a gate and found myself gazing down at a valley. After I’d been walking for a few minutes, looking at the fields and the sky, there was a shift in my perception.

A few years ago I climbed over a gate and found myself gazing down at a valley. After I’d been walking for a few minutes, looking at the fields and the sky, there was a shift in my perception.

As you read this, the screen is probably flashing over 240 times per second, yet, as a human, you won’t notice this flickering light. However, to a fruit fly hovering above your head, the screen would ...