CANNON-BARD THEORY OF EMOTION

In 1927, Cannon critically analyzed the James-Lange theory by reviewing relevant experimental and clinical research work, and put forth his theory of emotions.




The core of the Theory:
When emotional stimuli reach the cortex via the subcortical structures, an emotional experience along with activation of relevant peripheral bodily systems occurs.
e.g. We see a humorous event, and then simultaneously, there are bodily changes as well as experience of happiness.
Cannon believed that sub-cortical structures, especially the thalamus play the most important role in the experience of emotions. Thus his theory is also called the ‘Thalamic Theory’ sometimes.

He suggested, for example, that on seeing a bear, the sub-cortical structures inform the cortex about the threat and cause the activation of peripheral bodily systems that helps us to start running and also the experience of fear.
1. Total Separation of the Viscera from the CNS Does Not Impair Emotional Behavior
2. The Same Visceral Changes Occur In Diverse Emotional States And In Non-emotional States
3. The Viscera Are Relatively Insensitive Structures
4. Visceral Changes Are Too Slow To Be A Source Of Feeling
5. Artificial Induction of Visceral Changes Fails to Produce Emotions




1. Total Separation of the Viscera from the CNS Does Not Impair Emotional Behavior

Sherrington isolated the viscera and most of the muscles from the brain ofdogs by performing a high spinal transection.
No apparent change in emotional behavior of the dogs was observed.
In another experiment by Cannon, Lewis and Britton, the sympathetic nervous system of cats was surgically destroyed.
When exposed to a barking dog, these cats showed most sign of rage behavior – hissing, growling, baring of teeth, lifting the paw to strike (except erection of hair that is controlled directly by SNS).

James’ s supporters argued that though these experiments showed that the viscera are not necessary for emotional behavior, they did not prove that the animals actually FELT those emotions. Wynne & Solomon reported that sympathectomy delayed the learning of avoidance responding. These emotional behaviors could be merely learned responses and not actual reactions. However, if the sympathectomy was performed after the avoidance response was learnt, it had no affect on extinction. This shows that visceral arousal may help the acquisition of emotional behavior, but not its maintenance.
Hohmann interviewed 25 patients who had suffered injuries to their spinal-cords in accidents. All patients reported that their emotional experiences had decreased significantly as compared to the pre-accident period. Moreover, the more severe the injury, the higher was the reported loss of emotional-experiences. They reported ‘artificial’ and ‘hollow’ experiences, that lacked something very deep and important.




2. The Same Visceral Changes Occur In Diverse Emotional States And In Non-emotional States
e.g. The diffuse sympathetic-adrenal medulla response is quite similar in emotional and non-emotional states like fear, anger, fever, physical exertion, exposure to extreme heat and cold, etc.
Some supporter’s of James’s theory argued that skeletal muscles, rather than visceral systems create differences between emotional states.
Wolf and Wolf reported stomach motility and secretion and blood-vessel dilation occurred during anger, making the stomach lining red and inflamed.
Whereas, in depression or anxiety, it turned pale.
Shagass and Malmo, and Malmo, Kohlmeyer, and Smith, reported differential skeletal muscle tension during interviews of psychiatric patients.

e.g. Hostility – tension in forearm muscles
Sexual content – tension in leg muscles




3. The Viscera Are Relatively Insensitive Structures
Cannon pointed out that the viscera have very few sensory fibers, and thus we are unaware of what happens in the viscera most of the times.
Cannon’s argument is countered by some. They point out that the mere quantity of the sensory fibers need not be proof of their lack of contribution to emotional experience.

4. Visceral Changes Are Too Slow To Be A Source Of Feeling
Cannon argued that visceral responses take place slowly, whereas emotional experiences and expressions take place very fast. Thus, feedback from the viscera cannot be the source of emotional behavior.
Newman, Perkins and Wheeler found that some emotions were reported immediately, while some experiences were reported even 3 – 15 seconds after exposure to the stimuli. While this indicates that emotional experience is possible without feedback from the viscera, it also indicated that more complete, deeper emotional experiences may require visceral feedback.




5. Artificial Induction of Visceral Changes Fails to Produce Emotions
Cannon argued that if James-Lange Theory is to be accepted, epinephrine should produce emotional experiences.
Gregorio Maranon studied the effect of epinephrine by injecting 210 people with epinephrine. When interviewed, this 71 % of these individuals reported only physical symptoms. Some experienced emotions, but they were incomplete in some way. Very few experienced genuine emotions.

Cannon’s argument is countered by some. They point out that firstly, epinephrine has little effect on somatic functioning. Secondly, some of the individuals actually DID experience genuine emotions after being injected.