Before revision: The theory was challenged in the 1920s by psychologists such as Walter Cannon and Philip Bard, who developed an alternative theory of emotion known as Cannon–Bard theory, in which physiological changes follow emotions.
After revision: The theory was challenged in the 1920s by psychologists such as Walter Cannon and Philip Bard, who developed an alternative theory of emotion known as Cannon–Bard theory, in which physiological changes arise independently from emotions.