In the The Big Bang Theory episode (Season 4, Episode 20), the plot centers on a social experiment conducted by Sheldon and Amy to test the speed and "virulence" of gossip within their friend group. Plot Summary
: The engagement is particularly devastating for Raj, who had been harboring a secret crush on Bernadette and was hoping the breakup rumor was true. Key Episode Details [S4E20] The Herb Garden Germination
: Renowned physicist Brian Greene appears as himself, giving a book reading that Sheldon and Amy attend specifically to heckle. In the The Big Bang Theory episode (Season
: The episode concludes with Amy starting an even more extreme rumor—telling Penny she is pregnant with Sheldon's baby—to see how quickly Leonard finds out. Original Air Date April 7, 2011 Director Mark Cendrowski Major Milestone Howard and Bernadette get engaged : The episode concludes with Amy starting an
: Refers to the mundane "control" rumor Sheldon and Amy used for their social experiment.