“Men have a psychological need to show off their courage and strength. When he sees you talking to another guy, that instinct kicks in and he jumps to protect you and prove he's worthy of your love.”

American anthropologist, human behavior researcher, and self-help author

Helen Elizabeth Fisher was an American anthropologist, human behavior researcher, and self-help author. She was active in the late 20th and early 21st centuries, and is known for her work on human behavior and relationships. Fisher was a biological anthropologist and served as a senior research fellow at The Kinsey Institute of Indiana University. She was also a member of the Center for Human Evolutionary Studies in Rutgers University’s Department of Anthropology. Before that, she worked as a research associate at the American Museum of Natural History in New York City.