Whether it's coffee, alcohol, or perhaps something a little less legal, most people have experienced the mind-altering properties of the natural world.

But how did some plants become illegal while others are just part of the background hum of daily life? And how do they effect our brains?

Michael Pollan is an author and journalist and in his latest book This Is Your Mind on Plants, he takes a look at the science, history and social impact of caffeine, opium, and mescaline