Have you ever scrolled through social media and been surprised by an advert for something you were looking at the other day? This is no accident. Every view, every like, every click is stored, assessed and calculated, and allows the companies who run these platforms to target you with increasingly accurate advertising. But if you're not paying for the platform you're using, is there anything wrong with that? Well yes, according to Tristan Harris, one of the contributors to the successful Netflix documentary, The Social Dilemma. Social media may have started as a means of staying in touch with friends but it has led to multi-million pound businesses which use an economic model that competes for our attention, and Tristan fears this is doing society irrevocable harm.

Marcus Smith is a content creator from Bristol and a digital native. He is fascinated by technology's impact on us and has studied the effects of online gambling on young people. For 'One to One' Marcus is looking at the 'tech for good' movement and speaks to two leading figures in the tech industry - one who argues that it is currently a force for bad, and one who tries to work with tech to harness the good.

For this programme Marcus asks Tristan where he thinks we've gone wrong, and what social media companies, regulators and society should be doing about it.

Producer: Toby Field