Are angry male and female faces represented in opposite hemispheres of the female brain? A study using repetitive transcranial magnetic stimulation (rTMS)

The universality across cultures for recognizing the facial expression of anger suggests an evolved mechanism for dealing with threat. Using low frequency repetitive transcranial magnetic stimulation (rTMS) and a paradigm involving color-naming latencies for angry, fearful and neutral faces, and for emotional and neutral words respectively, we found evidence for a hemispheric specialization according to the sex and emotional content of faces in female subjects. Participants showed increased attention specifically to male angry faces after stimulation of the right superior temporal lobe, whereas they showed increased attention to angry female faces after left temporal stimulation. No effect was detected regarding the processing of fearful faces or emotional words. This result suggests differential processing of sex-specific threat-related stimuli specifically involving both hemispheres, i.e., that male and female faces are processed in opposite hemispheres, which might reflect the divergent adaptive significance of male and female threat for young females.