Mean facial muscle activity of receivers per odor condition during classification of presented (emotional) facial expressions.

<p>Odor condition: Baseline, fast stress, slow stress. Facial expressions that had to be classified: Neutral, happy, fear, disgust. For clarification purposes, the display of mean facial muscle activity on the emotional facial expression classification task was collapsed over the variable noise level (20%, 40%, 60%, 80%, 100%). (A) Mean <i>corrugator supercilii</i> activity, averaged over 1 second following the onset of the presented expression. (B) Mean <i>medial frontalis</i> activity, averaged over 1 second following the onset of the presented expression. Error bars reflect 68% within-subjects CI of the main effect of odor.