Dr. Elaine Aron's international bestseller The Highly Sensitive Person revolutionized how we view and identify highly sensitive people (HSPs). Dr. Aron found that not only 1 in 5 people are highly sensitive, but the trait occurs in the same percentage in over 100 other species. This trait (found in both men and women) reflects a certain type of survival strategy: being observant before acting. Sensitive-The Untold Story, a documentary based on Dr. Elaine Aron's work and featuring Alanis Morissette, was released in 2015.