Don't look back in anger: the rewarding value of a female face is discounted by an angry expression.

The modulating effect of emotional expression on the rewarding nature of attractive and nonattractive female faces in heterosexual men was explored in a motivated viewing paradigm. This paradigm, which is an indicator of neural reward, requires the viewer to expend effort to maintain or reduce image-viewing times. Males worked to extend the viewing time for happy and neutral attractive faces but to reduce the viewing time for the attractive angry faces. Attractive angry faces were rated as more aesthetically pleasing than the nonattractive faces; however, the males worked to reduce their viewing time to a level comparable with the nonattractive neutral and happy faces. Therefore, the addition of an angry expression onto an otherwise attractive face renders it unrewarding and aversive to potential mates. Mildly happy expressions on the nonattractive faces did little to improve their attractiveness or reward potential, with males working to reduce viewing time for all nonattractive faces.