This week on “The Learning Curve," Gerard and Cara talk with Loung Ung, a human-rights activist; the author of the bestselling books First They Killed My Father: A Daughter of Cambodia Remembers, Lucky Child, and Lulu in the Sky; and a co-screenwriter of the 2017 Netflix Original Movie, First They Killed My Father. Ms. Ung shares her experiences living through genocide under Pol Pot and the Khmer Rouge from 1975 to 1979, which resulted in the deaths of nearly a quarter of Cambodia's population.