You will see three color chips at a time, arranged in a triangle. Your job is simply to click the two that look most like each other. That’s the whole task — there are no right or wrong answers, only your eye.
There are two short stretches of these judgments with a pause between, about five minutes in all. It matters where the colors come from, but you’ll be told that at the end — knowing it now would spoil your data.
Your responses are recorded anonymously — no name, no login. What is recorded is which pairs you chose and how long you took. Best taken on a laptop or a phone held sideways, screen bright.