|MadSci Network: Neuroscience|
Hi Megan, Sorry for the delay, but I have been unable to find out much about the specific study you refer to in your question. A medline search of "physiognomy" and "Pennsylvania" only turned up one article from the University of Pittsburgh - which wasn't anywhere near your description. Perper JA, et al. Face imaging reconstructive morphography. A new method for physiognomic reconstruction. Am J Forensic Med Pathol. 1988 Jun;9(2):126-38. Searching for "physiognomy" and "stress" wasn't any better - two articles, but one in French, and the other in Romanian. Neither seemed relevant -- so I didn't try translating them for you ;-) So I'll try to fill you in on other information on the general topic of your question of facial muscle use. One early scientific work on this topic was done by someone that might surprise you - Charles Darwin. In 1872 he published " The expression of the emotions in man and animals" where he attempted to catalogue the expressions of humans and other animals and relate them to what he thought of as distinctive emotional states. He was one of the first scientists to view facial emotions as information that was communicated to other individuals (human or animal). More recently, Paul Ekman has been one of the major investigators in this arena of biopsychology. His research group has done a lot of work over the years to characterize and describe facial expressions of various human cultures in an objective fashion (important for interpretation). Simply put, Eckman and colleagues contend that there are seven (7) basic human emotions that are conveyed through facial muscles, and they are: anger, sadness, happiness, fear, disgust, surprise, and contempt. The really interesting thing about this finding is that Eckman's research group found these emotions across all the human cultures they studied. For example, if you were to make these facial expressions, a person in New Guinea or in South America, or in China would interpret your facial expression as the correct emotion. This suggests that there is some 'universality' of emotions across human cultures. However this work hasn't been accepted without criticism - Fridlund has suggested that emotions might not be as biological as Ekman believes. Rather, Fridlund believes that there are a number of emotions that occur specifically in social situations where there is a very social context to them that you can't interpret with a simple biological viewpoint. As far as other general information goes, facial expressions are very complex - involving numerous muscles, two different cranial nerves, and a number of different pathways in the central nervous system. Some people believe that voluntary facial movement (chewing, sticking our tongue out, raising our eyebrows) are very different from facial movement that is driven by emotion. This distinction comes from examining individuals who have damaged their motor cortex part of the brain (by way of accident or stroke). When asked to retract the corners of their mouths, they often have difficulty. However if you tell them a joke, they smile and laugh quite naturally (and in smiling, they retract the corners of their mouth). Folks with Parkinson's disease who have damage to subcortical regions of their brain (eg, basal ganglia) often show the reverse syndrome - they can move muscles voluntarily, but don't have any spontaneous emotional expression of the face. (I think these types of neurological studies are really interesting!). As far as your own study goes, I would suspect you might find interesting individual differences from taking split face photos and then recomposing them into L and R sided faces. Most individuals have very asymmetrical faces, as well as facial expressions (ie, the smile is stronger on one side than the other, or the eyes open more or less on one side). But as to whether all individuals show more or greater (or earlier) muscle movement on the left side - your guess is as good as mine (although I would play 'devil's advocate' and say that you probably won't find consistent differences across large numbers of people). I hope this helps somewhat - I've enclosed some references for your reading pleasure. Although they may be a little over a junior-high school head, you might also want to look up the topic 'facial expression and emotions' in a physiological psychology or biopsychology textbook as a better overview. Neil Carlson's textbooks have always been favorites of mine. Best of luck. Josh Rodefer, Ph.D. Harvard Medical School firstname.lastname@example.org EKMAN REFERENCES Ekman, P (1973). Darwin and faical expression; a century of research in review. Academic Press: New York. Ekman, P (1981). Methods for measuring facial action. In K. Scherer and P. Ekman (eds.) "Handbook on methods of nonverbal communications research." Cambridge University Press, New York. Ekman, P., and Davidson R.J. (1994). The nature of emotion: Fundamental questions. Oxford University Press, New York. Ekman, P. et al. (1983). Autonomic nervous system activity distinguishes among emotions. Science, vol 221, p, 1208-1210. FRIDLUND & SIMILAR REFERENCES Fridlund, A. (1988). What can asymmetry and laterality in EMG tell us about the face and brain? International Journal of Neuroscience, vol 39, p 53-69. Fridlund, A. (1994). Human facial expression: An evolutionary view. Academic Press, San Diego. Gilbert, A. N. et al (1986). Olfactory discrimination of mouse strains and major histocompatability types by humans. Journal of Comparative Psychology, vol 100, p 262-265. Kraut, R.E., and Johnston, R.E. (1979). Social and emotional messages of smiling: An ethological approach. Journal of Personality and Social Psychology, vol 37, p 1539-1533.
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