TARG researchers conducted a laboratory experiment with 48 healthy volunteers from Bristol, UK. An anxious state was created by fitting participants with a mask which delivered air enriched with carbon dioxide - a procedure which increases blood pressure, heart rate, and feelings of anxiety. In the control condition, the same participants inhaled normal air through the mask. Facial emotion processing abilities were assessed using computer tasks.

The researchers also found that when feeling anxious, participants who experience higher anxiety in general (trait anxiety) also tended to perceive anger rather than happiness in faces.

Misinterpreting social cues during anxious states could have negative emotional and social consequences. For example, perceiving anger instead of happiness (e.g., by thinking someone is frowning or staring), or failing to recognise happiness in neutral or ambiguous faces, could signal rejection or disinterest. This in turn could lead to negative feelings and emotions in the observer.