The Hawthorne effect is a seminal research study which is taught to every student of psychology. It states the basic principle that if people know they are being observed any change in the environment results in a change of behaviour, its that simple. But is that the whole truth? Nearly 100 years have passed since the Hawthorne study was started, the data has been reanalysed, new theories have arisen and decades of discussion and criticism was generated from this one study. This episode of A Brain talking about Brains (ABTAB) covers the initial studies, the aims of the researchers and how the study the research was done shaped it. With that setting complete I provide a historical retrospective and go from the 1920s to the modern day looking at all the ways the Hawthorne effect shaped the psychological world. Available on iTunes, Spotify, Stitcher, Overcast and our website. Please check out @WCNeuro, our WCNeuro facebook page and WCNeuro subreddit for more information on the episodes and series.