What is the Cannon-Bard theory of emotion?

The Cannon-Bard theory proposes that physiological arousal and the conscious experience of emotion occur simultaneously and independently rather than one causing the other. When you see a bear, the thalamus sends signals to the cortex producing the feeling of fear and to the autonomic nervous system producing arousal like increased heart rate at the same time. Cannon argued that bodily responses are too similar across emotions and too slow to precede emotional experience, contradicting the James-Lange theory.