CANALIZATION HYPOTHESIS. See MURPHY’S BIOSOCIAL THEORY.
CANNON/CANNON-BARD THEORY. The American physiologist Walter B. Cannon (1871–1945) is given the major initial credit for this theory, and the American psychologist Philip Bard (1898–1977) is given partial recognition for his research support in its development and refinement (Cannon, 1915, 1928, 1932; Bard, 1934a, b, 1950). Another name for this theory is the thalamic theory of emotion (Cannon, 1931). The Cannon–Bard theory proposes that the integration of emotional expressiveness is controlled and directed by the thalamus, which sends relevant excitation patterns to the cortex at the same time that the hypothalamus controls the behavior, and emphasizes the simultaneous arousal of both the central and autonomic nervous systems. Cannon argued that the function of the autonomic nervous system arousal was to prepare the organism to deal with the immediate event—to fight or to flee, for example. An event that might cause harm generates arousal (an ‘‘emergency response’’), which prepares the individual to cope with the event. Other alternative names for the Cannon–Bard theory, therefore, have been the fight or flight theory and the emergency theory. The Cannon–Bard theory was based on evolutionary survival value for the organism where increased heart rate, respiration, and so on permitted it to respond more quickly and strongly and, thereby, increased its chances of survival. The Cannon–Bard theory was a predominant opponent to the earlier James–Lange theory and argued that emotionality results from a removal of the inhibition that is normally exerted by the neocortex upon the thalamus. The neocortex, according to the Cannon–Bard approach, ordinarily suppresses the activity of the thalamus, but if emotion-eliciting stimuli reach the cortex, impulses are sent downward and act to release the inhibitory influences. Subsequently, the thalamus signals the neocortex to initiate the emotional experience while it also signals the rest of the body to begin the pattern of behavior