Why do we look back and yearn for the past, longing for some golden age when society was supposedly simple, innocent and kind? Why do we recall sweet memories of our youth? And the bitter-sweet memories of love and loss?Mike Williams speaks to a social psychologist who reveals that looking to the past can protect us in a number of surprising ways. He hears from a woman from the former German Democratic Republic who waxes nostalgic about life there. And he meets a man born in the 1970s who spends most of his time living in the 1940s.(Image of holiday makers waving at the seaside in 1930. Credit: Getty Images)