On June 13, 2009, Robert Sapolsky, world renowned professor of neurology, neurological sciences, neurosurgery and biological sciences gave the class day lecture in association with commencement weekend 2009. Having been selected to talk by the Stanford University graduating class, Sapolsky spoke about the uniqueness of humans in relation to the rest of the animal world. A few of the topics he spoke on include aggression, theory of mind, the golden rule and pleasure.