According to researchers at the University of York, a region of the brain, called the posterior superior temporal sulcus, can respond to both facial and vocal expressions of emotion.
Using the MagnetoEncephaloGraphic (MEG) scanner at the York Neuroimaging Centre to test responses in the region, the researchers found that the posterior superior temporal sulcus responds so strongly to a face plus a voice that it clearly has a 'multimodal' rather than an exclusively visual function.
For the study, participants were shown photographs of people with fearful and neutral facial expressions, and were played fearful and neutral vocal sounds, separately and together.
Responses in the posterior superior temporal sulcus were substantially heightened when subjects could both see and hear the emotional faces and voices, but not when subjects could both see and hear the neutral faces and voices.
They thought that the finding could help in the study of autism and other neuro-developmental disorders, which exhibit face perception deficits.
"Previous models of face perception suggested that this region of the brain responds to the face alone, but we demonstrated a supra-additive response to emotional faces and voices presented together - the response was greater than the sum of the parts," said lead researcher Dr Cindy Hagan.
Professor Andy Young added: "This is important because emotions in everyday life are often intrinsically multimodal - expressed through face, posture and voice at the same time."
The study is published in the latest issue of Proceedings of he National Academy of Sciences (PNAS).