AI-generated optical illusions can sort humans from bots
An AI-generated image of a city skyline and a man’s face – but AIs are unable to see both
Ziqi Ding et al. (2025)
Artificial intelligence programs can create optical illusions that other AIs are unable to recognise, creating a useful CAPTCHA test to differentiate humans from bots.
A cat-and-mouse game has played out for almost two decades between website developers who want to keep bots out of their sites and the hackers who want to bypass those protections. Websites have long deployed tests that are designed to be easy for humans to pass, but that trip up software.
