You will answer one question about each figure. Taking part is voluntary: you may stop at any time, and nothing is published unless you choose to publish at the end.
If published, your full response will be public: a random participant number, your colour-vision responses and results, figures and options, your selections and correctness, and study timings. Anyone may download and reuse this information.
We do not collect your name, contact details, IP address, or browser details. After consent, an essential cookie saves your progress and allows withdrawal for 24 hours after publication; a private code allows later withdrawal. Neither is published or used for tracking. Withdrawal removes our copy, not copies already downloaded.
The study contains 29 questions and takes approximately 15–20 minutes.