Computer scientists have developed artificial intelligence that can outsmart the Captcha website security check system.
Captcha challenges people to prove they are human by recognising combinations of letters and numbers that machines would struggle to complete correctly.
Researchers developed an algorithm that imitates how the human brain responds to these visual clues.
The neural network could identify letters and numbers from their shapes.
The research, conducted by Vicarious - a Californian artificial intelligence firm funded by Amazon founder Jeff Bezos and Facebook's Mark Zuckerberg - is published in the journal Science.
What is Captcha?