Fear is a survival instinctTo understand fear, it’s important to recognize the context in which it developed. For years, scientists doubted humans could smell fear since we lack a functioning organ to detect pheromones. How biology, empathy, and past experiences can shape our response to fearWe all share the brain circuitry that makes fear contagious. Whereas more empathetic individuals, when in the same situation, might feel fear more intensely. Holocaust descendants, for instance, have a heightened sensitivity to danger and therefore might feel fear more often.