Ben Hoyle, Los Angeles

Alexa had been quoting without context from Reddit, a social news aggregation siteLUKE MACGREGOR/BLOOMBERG/GETTY IMAGES

Alexa has a hidden dark side: last year the soft-voiced virtual assistant on Amazon’s Echo speakers urged a startled customer to “kill your foster parents”.

The user did not comply but did leave a harsh review on Amazon’s website, describing the episode as “a whole new level of creepy”.

A company investigation established that Alexa had been quoting without context from Reddit, a social news aggregation site that is notorious for its members’ trolling and abusive tone. The comments database had been opened to Alexa as part of an experiment to help it to communicate in a more sophisticated way.

Other gaffes arising from the scheme included Alexa regaling listeners with a lecture on dog excretion, chatting about sex and quoting a Wikipedia entry on…