Dr. Elaine Aron, author of The Highly Sensitive Person: How to Thrive When the World Overwhelms You, defines the Highly Sensitive Person (HSP) as someone who “has a sensitive nervous system, is aware of subtleties in his/her surroundings and is more easily overwhelmed when in a highly stimulating environment.” The research psychologist estimates 20 percent of the world’s population test positive for the HSP “trait.” Based on interviews with 40 subjects, she developed a self-test distributed to t …