Dr Daniel Glaser is back. To kick off season two he asks whether there is a connection between reward and addiction. And can we really get addicted to Twitter?

A Neuroscientist Explains: the evolutionary origins of social behaviour

Former Observer columnist Dr Daniel Glaser delves into topical culture as seen through the lens of a neuroscientist. Each episode, he takes one of his weekly columns and digs a little deeper, all with the help of former colleagues and neuroscientists from his research days