Facebook has been paying hundreds of outside contractors to transcribe voice chats carried out using the company's Messenger app, it has emerged.
The contractors - many from outsourcing firm TaskUs - were able to hear Facebook users' conversations, sometimes including "vulgar content", according to Bloomberg .
They were not told where the audio was recorded or why it needed to be transcribed, only to transcribe it.
This led some contractors to feel their work was unethical, according to the people with knowledge of the matter.
Facebook has confirmed the anonymous reports that it has been transcribing users’ audio, and said it will no longer do so, following scrutiny of other companies.
"Much like Apple and Google , we paused human review of audio more than a week ago," a spokesperson for the company said.
It added that contractors were checking the accuracy of Facebook's voice-to-text service in Messenger, which uses artificial intelligence to transcribe conversations.
Users who were affected chose to have their voice chats transcribed in Messenger and granted access to their phone's microphone for this purpose, according to Facebook.
However, they were not informed that clips of their conversations may be subjected to human review.
Facebook's data-use policy states that its systems "automatically process content and communications you and others provide to analyse context and what's in them."
But it includes no mention of other human beings screening the content.
The news comes after other major tech firms including Apple, Google and Amazon have all come under fire for their use of human workers to review voice recordings.
They claim that employees listen to these recordings in order to grade the responses of their AI voice assistants, and make them better at understanding and replying to users.
Apple and Google have both now paused their review programmes, and Amazon has given users the ability to opt out of having their voice recordings manually reviewed.
