Sleeping babies ‘tune into voices’

BABIES tune in to human voices even when they are asleep, according to new research.

Infants as young as three months old are also able to perceive different emotions from the voices they hear as they sleep, researchers from the Institute of Psychiatry (IoP) at King’s College London found.

Using functional magnetic resonance imaging (FMRI), they took brain images of sleeping babies and discovered that special areas in the brain which process sound are more sensitive than previously thought.

They found that from very early on in babies’ development, these special areas respond differently to different types of sound.

The team played a selection of emotionally neutral, positive or negative human sounds to babies aged between three and seven months old as they slept and recorded their brain responses.

The noises included coughing, sneezing, laughing or crying sounds, along with non-human environmental sounds such as noisy toys or water.

The results showed more activation in an area of the temporal lobe known for processing human vocal sounds in adults.

In another part of the brain involved in emotion processing in adults, the babies showed a marked increase in response to sad sounds as opposed to neutral ones.

The findings are consistent with earlier evidence that infants can extract subtle information from human speech.

Newborns prefer to listen to their mother’s voice and their mother tongue. Young infants can also differentiate between the voices of men and women, children and adults.

This research in normally developing babies will help researchers see what happens to this particular brain region in babies that go on to develop disorders such as autism, or abnormal social behaviours, in which social communication is affected.