Facebook has a knack for making controversial updates, and its latest algorithm is no exception. The company’s artificial intelligence team is currently testing an algorithm that can recognise people in photos even if their face is hidden from the camera.

Brilliant but creepy. So why is Facebook taking this risky step?

Experts have varying opinions. For one, facial recognition could help Facebook develop more products similar to its recently launched app Moments, which uses the technology to group photos together based on who is in each picture.

Another plausible scenario is that Facebook could use this technology in the future to help advertisers, academics and law-enforcement officials mine photos for clues about a person’s interests, social circles and activities.

The social media giant has been experimenting with facial recognition technology, also known as “faceprint” technology, since 2013 when it hired Yann LeCun, who is now head of its Artificial Intelligence team.

The experimental algorithm identifies people by reviewing their hairstyles, fashion preferences, postures and body shapes based on their existing photos, the New Scientist first reported. Facebook founder Mark Zuckerberg was used as an example of how the algorithm recognises clothing style, as he is popular for always wearing a gray t-shirt.

“We can easily picture Charlie Chaplin’s moustache, hat and cane or Oprah Windfrey’s curly volume hair,” Facebook said. “Yet, examples like these are beyond the capabilities of even the most advanced face recognisers.”

LeCun’s team experimented with around 40,000 public photos on Flickr, showing people whose faces are visible and people who are not looking at the camera. They were able to identify people with 83% accuracy using a method called PIPER or pose invariant person recognition.

The technology has been met with scrutiny from regulators and privacy advocates in the US and Europe as well. According to Mike Weston, chief executive of London-based data-science consulting group Profusion, having people’s faces recognised without their consent is a violation of their right to a private life.

Facebook’s Moments app has been banned in Europe due to its facial recognition technology.