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Sex differences in neural activation to facial expressions denoting contempt and disgust.

Aleman A, Swart M - PLoS ONE (2008)

Bottom Line: Contemptuous faces did not elicit stronger amygdala activation than did disgusted expressions.In addition, the effect of stimulus sex differed for men versus women.Thus, our results suggest a neural basis for sex differences in moral sensitivity regarding hierarchy on the one hand and physical purity on the other.

View Article: PubMed Central - PubMed

Affiliation: BCN Neuroimaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. a.aleman@med.umcg.nl

ABSTRACT
The facial expression of contempt has been regarded to communicate feelings of moral superiority. Contempt is an emotion that is closely related to disgust, but in contrast to disgust, contempt is inherently interpersonal and hierarchical. The aim of this study was twofold. First, to investigate the hypothesis of preferential amygdala responses to contempt expressions versus disgust. Second, to investigate whether, at a neural level, men would respond stronger to biological signals of interpersonal superiority (e.g., contempt) than women. We performed an experiment using functional magnetic resonance imaging (fMRI), in which participants watched facial expressions of contempt and disgust in addition to neutral expressions. The faces were presented as distractors in an oddball task in which participants had to react to one target face. Facial expressions of contempt and disgust activated a network of brain regions, including prefrontal areas (superior, middle and medial prefrontal gyrus), anterior cingulate, insula, amygdala, parietal cortex, fusiform gyrus, occipital cortex, putamen and thalamus. Contemptuous faces did not elicit stronger amygdala activation than did disgusted expressions. To limit the number of statistical comparisons, we confined our analyses of sex differences to the frontal and temporal lobes. Men displayed stronger brain activation than women to facial expressions of contempt in the medial frontal gyrus, inferior frontal gyrus, and superior temporal gyrus. Conversely, women showed stronger neural responses than men to facial expressions of disgust. In addition, the effect of stimulus sex differed for men versus women. Specifically, women showed stronger responses to male contemptuous faces (as compared to female expressions), in the insula and middle frontal gyrus. Contempt has been conceptualized as signaling perceived moral violations of social hierarchy, whereas disgust would signal violations of physical purity. Thus, our results suggest a neural basis for sex differences in moral sensitivity regarding hierarchy on the one hand and physical purity on the other.

Show MeSH
Bilateral activation of amygdala during perception of contempt and disgust expressions (shared activation; conjunction analysis).
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pone-0003622-g001: Bilateral activation of amygdala during perception of contempt and disgust expressions (shared activation; conjunction analysis).

Mentions: Subjects on average identified the target correctly on 98.7% of trials, with 1.4% of false alarms. Across all participants, facial expressions of contempt and disgust (relative to random dot patterns) activated a network of brain regions that included prefrontal areas (superior, middle and medial prefrontal gyrus), anterior cingulate, insula, amygdala, parietal cortex, fusiform gyrus, occipital cortex and putamen and thalamus. Neutral expressions also activated these areas, with exception of insula and cingulate/prefrontal areas. The different types of expressions did not differ in terms of amygdala activation, which was robust and bilateral (see figure 1 for the shared amygdala activation during contempt and disgust as revealed by a conjunction analysis). The amygdala activation also survived a higher threshold of k = 20 and FDR correction (at P<0.001). Because of the strong a priori hypothesis regarding preferential amygdala activation for contempt, we conducted an additional analysis in which we lowered the threshold to a liberal value of P = 0.005, uncorrected. Contrary to the hypothesis, the contrast of contempt versus disgust yielded significant stronger amygdala activation for disgust relative to contempt, 7 voxels, peak t-value 4.06, peak coordinates 31, −3, −11.


Sex differences in neural activation to facial expressions denoting contempt and disgust.

Aleman A, Swart M - PLoS ONE (2008)

Bilateral activation of amygdala during perception of contempt and disgust expressions (shared activation; conjunction analysis).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2572192&req=5

pone-0003622-g001: Bilateral activation of amygdala during perception of contempt and disgust expressions (shared activation; conjunction analysis).
Mentions: Subjects on average identified the target correctly on 98.7% of trials, with 1.4% of false alarms. Across all participants, facial expressions of contempt and disgust (relative to random dot patterns) activated a network of brain regions that included prefrontal areas (superior, middle and medial prefrontal gyrus), anterior cingulate, insula, amygdala, parietal cortex, fusiform gyrus, occipital cortex and putamen and thalamus. Neutral expressions also activated these areas, with exception of insula and cingulate/prefrontal areas. The different types of expressions did not differ in terms of amygdala activation, which was robust and bilateral (see figure 1 for the shared amygdala activation during contempt and disgust as revealed by a conjunction analysis). The amygdala activation also survived a higher threshold of k = 20 and FDR correction (at P<0.001). Because of the strong a priori hypothesis regarding preferential amygdala activation for contempt, we conducted an additional analysis in which we lowered the threshold to a liberal value of P = 0.005, uncorrected. Contrary to the hypothesis, the contrast of contempt versus disgust yielded significant stronger amygdala activation for disgust relative to contempt, 7 voxels, peak t-value 4.06, peak coordinates 31, −3, −11.

Bottom Line: Contemptuous faces did not elicit stronger amygdala activation than did disgusted expressions.In addition, the effect of stimulus sex differed for men versus women.Thus, our results suggest a neural basis for sex differences in moral sensitivity regarding hierarchy on the one hand and physical purity on the other.

View Article: PubMed Central - PubMed

Affiliation: BCN Neuroimaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. a.aleman@med.umcg.nl

ABSTRACT
The facial expression of contempt has been regarded to communicate feelings of moral superiority. Contempt is an emotion that is closely related to disgust, but in contrast to disgust, contempt is inherently interpersonal and hierarchical. The aim of this study was twofold. First, to investigate the hypothesis of preferential amygdala responses to contempt expressions versus disgust. Second, to investigate whether, at a neural level, men would respond stronger to biological signals of interpersonal superiority (e.g., contempt) than women. We performed an experiment using functional magnetic resonance imaging (fMRI), in which participants watched facial expressions of contempt and disgust in addition to neutral expressions. The faces were presented as distractors in an oddball task in which participants had to react to one target face. Facial expressions of contempt and disgust activated a network of brain regions, including prefrontal areas (superior, middle and medial prefrontal gyrus), anterior cingulate, insula, amygdala, parietal cortex, fusiform gyrus, occipital cortex, putamen and thalamus. Contemptuous faces did not elicit stronger amygdala activation than did disgusted expressions. To limit the number of statistical comparisons, we confined our analyses of sex differences to the frontal and temporal lobes. Men displayed stronger brain activation than women to facial expressions of contempt in the medial frontal gyrus, inferior frontal gyrus, and superior temporal gyrus. Conversely, women showed stronger neural responses than men to facial expressions of disgust. In addition, the effect of stimulus sex differed for men versus women. Specifically, women showed stronger responses to male contemptuous faces (as compared to female expressions), in the insula and middle frontal gyrus. Contempt has been conceptualized as signaling perceived moral violations of social hierarchy, whereas disgust would signal violations of physical purity. Thus, our results suggest a neural basis for sex differences in moral sensitivity regarding hierarchy on the one hand and physical purity on the other.

Show MeSH