Can the recognition of emotional expressions be enhanced by manipulating facial skin color?

Trichromacy might have evolved in primates for the purpose of emotion recognition [1]. Emotional states change the quantity of blood and its oxygenation under the skin, which cause subtle changes in skin color to become visible, especially in the face. We manipulated photos of basic emotional expressions so that skin color was either congruent or incongruent (according to [1]) with the expression. Thirty-five participants selected emotional labels for each expression. We predicted that enhanced but congruent colors would improve performance, whereas enhanced but incongruent colors should worsen discriminating emotions correctly. The findings weakly supported the hypotheses. Finally, the Farnsworth-Munsell 100 Hues Test revealed that errors correlated negatively with accuracy in the task, supporting the idea that color ability benefits the recognition of emotions.