Abstract
In this reply, I focus on the question of whether Cannon’s theory was (only) a “centralized” version of James’s. Due to space limitations, I briefly present six observations that problematize this assertion. One of my guiding principles is that theories acquire their meaning within a particular context. From this historical perspective, and in their historical contexts, the theories were quite distinct.
In this reply, I focus on the question of whether Cannon’s theory was (only) a “centralized” version of James’s (1884). Due to space limitations, I briefly present six observations that problematize this assertion. One of my guiding principles is that theories acquire their meaning within a particular context. The question of whether Cannon’s and James’s theories were and are analogous is thus time/context dependent. Reisenzein and Stephan (2014) have provided an interesting and thought-provoking interpretation of Cannon’s theory from a contemporary perspective/context. From an historical perspective, and in their historical contexts, the theories were quite distinct.
The first important distinction between Cannon and James was that Cannon’s model, unlike James’s, was a release model of emotions. In Cannon’s model, the cortex continuously inhibited the thalamus; emotion was a state of “release” from this inhibition. This distinction presented a radically different conception of the relationships between cortex and emotions. It suggested myriad new explanatory schemes and interactive possibilities between the cortex and the thalamic center/s. One brief example will have to suffice: The new model clearly distinguished between the differential controls of the thalamus versus the cortex over visceral versus skeletal-muscle expressions of emotions. This distinction was important in cases of “conflict” between cortex and thalamus and in explaining the subjective experience of “confusion” during emotion (Cannon, 1928, p. 880; Howard, 1928, p. 148). These new types of explanatory models, which drew on new interactive schemes between cortex and thalamus, became available with Cannon’s new model.
A second important distinction pertained to different classes of emotions. Unlike James’s model, Cannon’s explicitly proposed different mechanisms for different categories of emotions. Cannon clearly distinguished between strong/vehement versus subtle emotions. This distinction was crucial for Cannon, since his thalamic theory of emotions, as he explicitly argued, explained only four to five emotions: rage, fear, joy, grief (and disgust). Excepting these five emotions, all other emotional reactions were explainable in terms of conditioning, which Cannon introduced into his model in drawing on Pavlov’s work. James’s theory, in contrast, did not propose categorical distinctions between or differential mechanisms for different classes of emotions.
A third important distinction between the theories was the explicit positioning of the source of emotions in the lower, evolutionarily more archaic parts of the brain, in Cannon’s model. Bard had explicitly argued to this effect in presenting the neuro-anatomical scheme of emotions (Bard, 1928, p. 509). The framing of the relationships between emotion and cortex in terms of an evolutionary scheme of the neuro-anatomy of emotions in Cannon’s model was highly significant for future models of emotions.
Cannon’s shift to the brain also contributed importantly to a more general shift of the study of emotions to the brain. Though the brain had obviously been an object of study prior to Cannon, most laboratory-based researchers of emotions during the 19th century focused on the body. It was only after Cannon introduced his model that physiologists and anatomists of emotions shifted in large numbers to the brain in the study of the anatomy and physiology of emotions.
Cannon’s new brain-centered model of emotions was also important for, and was integrated into, new and emerging fields during the interwar years. Cannon’s model was significant for the development of the emerging fields of stress research and the new psychosomatic medicine of the interwar period (Dror, in press). Indeed, the first issue of the new journal Psychosomatic Medicine (1939) dedicated over 100 pages (!) to articles that focused on the hypothalamus as the site where psychology met physiology, and where emotions were physiologized. In addition, the hypothalamus was not only a locus for emotions, but also for other functions in the body. The anatomical proximity of the center/s of emotion to other centers in the hypothalamus suggested new mechanisms for psychosomatic interrelationships through the mechanism of local irradiation in the hypothalamus. Cannon’s theory also provided psychiatrists with new models of psychopathology. According to these new models, psychopathologies, like mania or bouts of uncontrollable rage, were states in which the lower centers of the thalamus overtook the cortex. Cannon’s centralized model also seemed to fit a Freudian scheme. In this suggestive scheme, the hypothalamus was the locus of the “Id.”
Last, I would suggest that Cannon was somewhat vague regarding the question of whether the neurons that fired downward to create the expression were the same neurons that fired upward to the cortex. As Cannon put it: The thalamic neurons “not only innervate muscles and viscera but also excite afferent paths to the cortex by direct connection or by irradiation” (Cannon, 1927, p. 120).