Babies link vocal and facial emotions, say Swiss researchers

The research found that babies are sensitive to changes in the mouth expressions of the person they are looking at. 123RF

Babies can differentiate between happiness and anger, say Swiss researchers using eye-tracking technology to record how babies react to faces after hearing voices.

In a study of 24 six-month-olds, researchers from the University of Geneva discovered that babies look at an angry face – especially the mouth – for longer if they have just heard a happy voice. This reaction demonstrates for the first time that babies have an early ability to transfer emotional information from the auditory mode to the visual.

The study took place at the Geneva BabyLabExternal link. During the first phase, the babies faced a black screen and listened to a neutral, happy or angry voice for 20 seconds. In the second phase, the babies were shown two emotional faces – one expressing happiness and the other anger – for ten seconds while the researchers used eye-tracking technology to focus on the babies’ eye movements.

They were then able to determine whether the time spent looking at one or other of the emotional faces – or specific areas of the face (the mouth or eyes) – varied according to which voice they listened to.

“If they clearly looked at one of them much longer, we could state that they are able to spot a difference between the two faces,” explains Amaya Palama, a researcher at the laboratory of sensorimotor, affective and social development in the university’s faculty of psychology and educational sciences. It seems that babies prefer what is new and surprising.

Funded by the Swiss National Science Foundation, the research is part of a project designed to examine the development of childhood emotional discrimination abilities. The findings have been published in the journal PLOS ONE.