Humans are thought to be born with only two instinctive fears: sudden loud sounds and falling or heights. Psychologists link these reactions to survival mechanisms present in infancy. Most other fears, including fear of animals, darkness, or social situations, are believed to develop later through personal experiences, parenting, culture, and environmental conditioning throughout life. MLA Source: Watson, John B., and Rosalie Rayner. “Conditioned Emotional Reactions.” Journal of Experimental Psychology, vol. 3, no. 1, 1920, pp. 1–14. Conditioned Emotional Reactions Study Want more interesting content like this ? Follow gravitonomy :) #acrophobia #heights #science