Submitted by Armen Hareyan on Aug 8th, 2005
Brain
Scientists at the University of Sheffield have explained the differences in the way the male brain interprets male and female voices, explaining why people who hallucinate and hear false voices almost always hear a man. It also sheds new light on the way the brain processes voices to produce an 'auditory face' that allows people to determine aspects of someone's physical appearance based solely on the way they sound.
The paper, published online in NeuroImage, describes how scientists studied brain scans of 12 male subjects whilst they listened to male and female voices. It found startling differences in the way that the brain interprets the two sounds, with female voices causing activity in the auditory section of the brain and the male voice sparking activity in the 'mind's eye' at the back of the brain.
Dr Michael Hunter, of Professor Peter Woodruff's group in the Department of Psychiatry and Division of Genomic Medicine at the University of Sheffield, and co-author of the study explains, "Voices allow the brain to determine various factors about a person's appearance, including their sex, size and age. It is much more complex than most people think and is an extremely important tool for determining someone's identity without having to see them.
"The female voice is actually more complex than the male voice, due to differences in the size and shape of the vocal cords and larynx between women and men, and also due to women having greater natural 'melody' in their voices. This causes a more complex range of sound frequencies than in a male voice.
"When a man hears a female voice the auditory section of his brain is activated, which analyses the different sounds in order to 'read' the voice and determine the auditory face.
"When men hear a male voice the part of the brain that processes the information is towards the back of the brain and is colloquially known as the 'mind's eye." This is the part of the brain where people compare their experiences to themselves, so the man is comparing his own voice to the new voice to determine gender.
"People who hear hallucinatory voices usually hear male voices. Psychiatrists believe that these auditory hallucinations are caused when the brain spontaneously activates, creating a false perception of a voice. The reason these voices are usually male could be explained by the fact that the female voice is so much more complex that the brain would find it much harder to create a false female voice accurately than a false male voice.
"This research could also explain why female voices are considered to be clearer then male voices. This could be linked to the fact that female voices are interpreted in the auditory part of the brain, and are therefore more easily decoded."
Source:
The University of Sheffield 