The intensity of emotional facial expressions and decoding accuracy

The influence of the physical intensity of emotional facial expressions on perceived intensity and emotion category decoding accuracy was assessed for expressions of anger, disgust, sadness, and happiness. The facial expressions of two men and two women posing each of the four emotions were used as stimuli. Six different levels of intensity of expression were created for each pose using a graphics morphing program. Twelve men and 12 women rated each of the 96 stimuli for perceived intensity of the underlying emotion and for the qualitative nature of the emotion expressed. The results revealed that perceived intensity varied linearly with the manipulated physical intensity of the expression. Emotion category decoding accuracy varied largely linearly with the manipulated physical intensity of the expression for expressions of anger, disgust, and sadness. For the happiness expressions only, the findings were consistent with a categorical judgment process. Sex of encoder produced significant effects for both dependent measures. These effects remained even after possible gender differences in encoding were controlled for, suggesting a perceptual bias on the part of the decoders.