5. The Vortex

One of the strange things about our new media universe, is how innocuous decisions taken in Silicon Valley - turning a dial, or adding a few lines of code to increase engagement - can change your life.

In 2016, Instagram introduced a new way of looking at content: the non-chronological feed.

Now, instead of seeing what your friends were posting in the order they were posting it, an algorithm brought you stuff based on search history, likes, and interactions.

That’s how tech engineers saw things back then - not just at Instagram, but at Pinterest, and other platforms too - if you engage with something, that must mean you want more of it.

Ian Russell believes that this algorithmic change may have altered the course of his 14 year old daughter Molly's life.

Presenter: Jamie Bartlett

Producer: Caitlin Smith

Sound Design: Eloise Whitmore

Composer: Jeremy Warmsley

Story Consultant: Kirsty Williams

Execuitve Producer: Peter McManus

Commissioner: Dan Clarke