Dr Michael Mosley puts human behaviour under the microscope in this bold new series that uses the latest scientific studies to explore the evolutionary factors and animal instincts that drives human behaviour. A plush country house is fixed with surveillance cameras while a group of unwitting test subjects - former pupils of a UK school - are first exposed to youthful memories to test if it can improve their health. This episode looks at how we behave in groups and puts our notions of hierarchy to the test.