Post auricular and eye blink startle response to facial expressions
Hess, U., Sabourn, G., Kleck, R.E. (2007)
Psychophysiology, 44 , 431-435
Facial morphological cues depend on the sex (KRO and? race) of the expressor and in this way gender (? sex & race) can modulate the perception of facial expression – (see Hess functional equivalence hypothesis for interaction with expression).
Both the startle blink reflex & the post auricular reflex are modulated by emotional state; + for unpleasant, - for pleasant for the eye blink; - for unpleasant, + for pleasant for post auricular. The amplitude of this effect varies with the stimulus used to induce emotional state facial expression being less reliable than some other stimuli despite other indicators that facial expressions is important for both for inducing of emotion, the contagion effect, Baliry, Herrera & Hess, 1999, Hess & Blairy, 2001) and for signalling emotional state whether spontaneously or voluntarily
Recognising commonalities with communicative signal systems of animals could be extrapolated to the assumption that anger signals dominance and happiness affiliation. Keating et al 1981; Senior et al, 1999, Berry & McAuthur, 185,1986) claims in humans these dispositions, dominance and affiliation, are signalled by facial morphology which tends to be gender typical, for example male square jaw and female round face and large eyes. At the same time specific patterns of facial movement can also signal anger and happiness.
P432 Hess, Adams & Kleck (2007) have proposed ‘a functional equivalence hypothesis that postulates that facial expressive behaviour & morphological cues to dominance and affiliation are similar in their effects on emotional attributions This notion also implies that there are interactions between facial expression and facial morphology in the decoding of expressions of emotion’
Three aims
1. Assess eye blink startle and post auricular responses during exposure to emotional facial expressions.
They occur. In discussion the authors consider the function of valence which they see as a ‘shortcut referring to an underlying association of negative valence and withdrawal or submission and positive valence and approach’ they also imply that valence is carried by expression. KRO this would be compatible with the idea of the neural input as sub cortical and therefore more primitive.
2. Happiness when displayed by a women is more appetitive, whereas anger when shown by a man is more threatening.
Therefore expect
potentiated post auricular for female happiness when compared to male happiness
potentiated eye blink for male anger compared to female anger
Results consistent with this hypothesis.
3. Non social emotional scenes used to validate the emotional modulation of the post auricular response as reported by Benning et al, 2004
Results consistent.
Experiment
Undergraduates, (facial & scene) images as stimuli, post auricular measured as EMG to 50 ms duration white noise at 95dB.
