Emotions love, hate, happiness, sadness, fear, anxiety, and so on are feelings we all experience at one time or another.
In the nineteenth century, several highly regarded scientists, including Darwin and Freud, considered the role of the brain in the expression of emotion.
Later in the nineteenth and twentieth centuries, scientists developed theories for the physiological basis of emotion and the relationship between emotional expression and experience.
Introduction to the James–Lange Theory of Emotion
One of the first well-articulated theories of emotion was proposed in 1884 by the renowned American psychologist and philosopher William James. Similar ideas were proposed by Danish psychologist Carl Lange.
This theory, commonly known as the James–Lange theory of emotion, proposed that we experience emotion in response to physiological changes in our body. The emotion you experience consists of your feelings that result from the changes in the body. The James–Lange theory is the exact opposite of the common conception that an emotion is evoked by a situation and the body changes in response to the emotion.
Physiological Basis and Implications of the James–Lange Theory
Even if it is true that emotion follows from changes in the body’s physiological state, this doesn’t mean that emotion cannot be felt in the absence of obvious physiological signs.
But for strong emotions that are typically associated with physical change, the James–Lange theory says the bodily changes cause the emotion rather than the other way around.
Cannon–Bard Theory: A Response to James–Lange
In 1927, American physiologist Walter Cannon published a paper that offered several compelling criticisms of the James–Lange theory and proposed a new theory.
Cannon’s theory was modified by Philip Bard and became known as the Cannon–Bard theory of emotion.
It proposed that emotional experience can occur independently of emotional expression.
Cannon noted human cases in which a transected spinal cord did not diminish emotion.
If emotional experience occurs when the brain senses physiological changes in the body, as the James–Lange theory proposed, then eliminating sensation should also eliminate emotions, and this did not appear to be the case.
Role of the Thalamus in Emotional Processing
Cannon’s new theory focused on the idea that the thalamus plays a special role in emotional sensations. Emotions are produced when signals reach the thalamus either directly from the sensory receptors or by descending cortical input.
According to Cannon’s theory, you don’t have to cry to feel sad; there simply has to be the appropriate activation of your thalamus in response to the situation. Many theories of emotion have been proposed since the days of the James–Lange and Cannon–Bard theories.
Challenges and Revisions to Early Emotion Theories
Research has also shown that to some extent we can be aware of our body’s autonomic function, a key component of the James–Lange theory. Another interesting challenge to the Cannon–Bard theory, demonstrated by later studies, is that emotion is sometimes affected by damage to the spinal cord. In one study of adult men with spinal injuries, there was a correlation between the extent of sensory loss and reported decreases in emotional experiences. Several related experiments were conducted by Arne Öhman, Ray Dolan, and their colleagues in Sweden and England. These findings indicate that the subjects responded to the angry expressions on the aversive face stimuli even though they were not perceptually aware of seeing the faces at all.
Unconscious Emotional Responses: Experimental Evidence
For now, the important point to remember is that measures of both autonomic response and amygdala activity correlate with the presentation of angry faces that are conditioned to be unpleasant despite the fact that the faces are not perceived. If sensory signals can have emotional impact on the brain without our being aware of it, this seems to rule out theories of emotion in which emotional experience is a prerequisite for emotional expression.
Implications for Brain Pathways and Emotional Processing
We now turn to the pathways in the brain that link sensations (inputs) to the behavioral responses (outputs) that characterize emotional experience. Different emotions may depend on different neural circuits, but some parts of the brain are important for multiple emotions.
