Paul Ekman, a prominent psychologist, revolutionized the understanding of emotions by proposing that six basic emotions—anger, disgust, fear, joy, sadness, and surprise—are universal and have biological roots rather than cultural ones. His research emphasized the connection between facial expressions and emotions, demonstrating that these reactions have evolved as survival mechanisms. Though some in the scientific community challenge his findings, Ekman's work has significantly influenced the field of psychology and understanding of nonverbal communication.