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Posed emotional expression in unilateral brain damaged patients
C Caltagirone1, P Ekman, W Friesen
1Institute of Neurology, II University of Rome.
Summary
This study found no differences in posing facial expressions between patients with right or left brain damage and healthy individuals. These results challenge the idea that the right hemisphere uniquely controls posed emotional expressions.
Area of Science:
- Neuroscience
- Psychology
- Cognitive Science
Background:
- The role of specific brain hemispheres in controlling voluntary facial expressions is debated.
- Previous hypotheses suggested a dominant role for the right hemisphere in emotional expression.
Purpose of the Study:
- To investigate whether right or left hemisphere brain damage affects the ability to pose facial expressions of basic emotions.
- To test the hypothesis of right hemisphere specialization for posed facial expressions.
Main Methods:
- Posed facial expressions of six basic emotions were elicited from patients with right (N=23) and left (N=34) brain damage, and a control group (N=28).
- Facial expressions were analyzed using the Facial Action Coding System (FACS) for objective scoring and a subjective appropriateness scale.
Main Results:
- No significant differences were found in the ability to pose facial expressions between the control group and patients with either right or left hemisphere lesions.
- The findings do not support the hypothesis that the right hemisphere is specifically involved in controlling posed facial expressions.
- No correlation was observed between posed emotional expression and the presence of facial paralysis or oral apraxia.
Conclusions:
- The ability to voluntarily pose facial expressions of basic emotions does not appear to be lateralized to the right hemisphere.
- Brain damage to either hemisphere does not uniquely impair the generation of posed facial expressions, suggesting bilateral or non-hemispheric control mechanisms.