James Lange theory

The James-Lange Theory states that a stimulus immediately affects the autonomic nervous system and then the message is sent to the brain.

William James and Carl Lange proposed one of the earliest theories on how our emotions worked. This has been called the James-Lange theory. This suggests that when we perceive a threatening stimulus such as a very large spider near us, the perception immediately affects the autonomic nervous system. This creates a specific response with increases in things such as blood pressure, heart rate and breathing. This theory assumes a different pattern of physiological response for each emotion - as the message is then sent to the brain about the type of response, which is then assessed and we experience the relevant emotion. One of the main criticisms of this theory is that there is very little difference between the physiological patterns of arousal in a number of emotions such as anger, fear and sadness, yet our facial expression, body reaction and the way we rate the experience differ a lot.

The Canon - Bard Theory

In 1929, Walter Canon proposed another theory that examined just how emotions worked. This was modified by Philip Bard and became known as the Cannon Bard theory. While this has some links with the James Lange theory, the direction of the initial stimulus is different. This theory suggests that when a person faces an event that affects them, the message collected from the sensory system travels to the thalamus in the brain. Here the message divides. One part goes to the cortex where we have a conscious subjective experience of the emotion such as fear, anger, surprise or joy. This is what people will say when asked what they are "feeling" The other part goes to the hypothalamus which then triggers off the physiological changes as well as the facial expression and body language that goes with certain responses.