My brother is nonverbal, autistic and very low functioning. I don’t know if I will ever be able to communicate with him on any level but the most basic, i.e., Food=Good, No Food=Not Good.
If it is true that every person has a mental state of some kind, and that mental states are reflected in a physical expressions of some kind, could we reverse the process and infer a mental state from a person’s expression?
In this part, I survey the basis for what would seem to be an obvious connection between expression and emotion, or mental state. In part 2, I explore the reversal of this process: inferring as state of mind from an expression.
From Whence do Expressions Come?
I am reading The Expression of the Emotions in Man and Animals by Charles Darwin. He gathered information from many sources about a wide range of facial and postural expressions in man and animals. Darwin proposed that expressions have a pattern of development, beginning as voluntary actions, becoming habitual and finally becoming hereditary. He stated, “That the chief expressive actions, exhibited by man and by the lower animals, are now innate or inherited – that is, have not been learnt by the individual, – is admitted by every one.”
Darwin suggested three principles of expression:
1) The principle of serviceable associated Habits: complex interactions of nerve and muscle, resulting in an expression, indicate a man or animal’s state of mind.
2) The principle of Antithesis: an opposite state of mind results in an “involuntary tendency to the performance of movements of a directly opposite nature…”
3) The principle of actions due to the constitution of the Nervous System, independently from the first of the Will, and independently to a certain extent of Habit. Darwin restates the third principle as the interactions of nerve and muscle result from “the direct action of the nervous system” [emphasis added].
Darwin’s observations and those of his associates, together with their rudimentary experiments led to the conclusions, that expressions arise first from voluntary action to environmental stimulus, become habitual, and finally become innate and inheritable. Furthermore, he concluded that expressions result from action of the nervous system and that they reflect a state of mind.
From Whence do Emotions Come?
As mentioned in a previous post, the limbic system, present in all mammals, consisting of structures along the midline of the brain has been identified as being responsible for emotions. James Papez discovered in 1937 that these midline structures function in the same manner as other somatosensory systems, i.e., the sensory nerve fibers have a relay station in the thalamus. Dr. Paul MacLean suggested that the hippocampus, the amygdala and septum be included in Papez’s circuit. The limbic system has rich neuronal connections with other parts of the brain. In addition, the limbic system has access to the chemical control system through the hypothalamus (i.e., hormone levels and other systems, which act to heighten or dull senses globally). “The Circuit of Papez also includes other cerebral regions with locomotor, mnemic and associative functions.”
How does Emotion Connect with Expression?
There are many structures which have input to the ‘emotional circuit’; too many to delve into in this forum. Suffice it to say, there is evidence of connection of the ‘emotional circuit’ with the ‘nerve-force’ that Darwin suggests is the origin of expression. For instance, Dr. Pierre Gloor eminent physician and epilepsy researcher stated that “the limbic system… embodies mechanisms that relate “external” reality perceived by the exteroceptive senses to “internal” reality embedded in memory and affect.” Other connections have been noted. Morecraft and Van Hoesen “… suggest that the cingulate motor cortex form a strategic cortical entry point for limbic influence on the voluntary motor system.”
We Have all the Ingredients
I have not done an exhaustive survey of the literature regarding the relationship between emotions and expression. This is a topic that I would like to revisit in future posts. However, it is clear that a mechanism for translating an inner emotion, or state of mind to the rest of the body exists.
 Darwin, C The Expression of the Emotions in Man and Animals. U. of Chicago Press (1965)
 Ibid pg 350
 Ibid pg28-29
 My favorite part of the brain!
 Mnemic definition: the retentive basis or basic principle in a mind or organism accounting for memory. dictionary.reference.com/browse/mnemic
 Roxo, M.R. et. al The Limbic System Conception and Its Historical Evolution Scientific World Journal. 2011; 11: 2428–2441.
 Affect (appearance) is an important notion that I would like to discuss in a future post.
 Gloor, P. The Temporal Lobe and Limbic System. Oxford University Press (1997)
 Morecraft, R. J., Van Hoesen, G. W. (1998). Convergence of limbic input to the cingulate motor cortex in the rhesus monkey. Brain Res Bull 45: 209–32