Reward centre in the brain is activated by looking at cute facial features

The baby schema felt to be cute contains a series of child-like physical features, e.g. a large head with a high forehead, round cheeks and big eyes. Numerous behavioural studies have confirmed the effect of the baby schema on adults.

For example, a team of researchers led by Melanie Glocker from the Institute of Neural and Behavioural Biology at the University of Münster already showed just recently that children who correspond more strongly to the baby schema increase a willingness to show caretaking behaviour. This reaction is stronger in women than in men, even though both sexes perceive the cuteness equally.

However, not much was known hitherto about the neuro-biological basis of this fundamental social instinct which could be the basis for caretaking and altruistic behaviour. In collaboration with a team of colleagues from Pennsylvania led by Prof. Ruben Gur, the Münster neuroscientists Melanie Glocker and Prof. Norbert Sachser have shown in a new study for the first time what goes on in the brain as a reaction to the baby schema. “The results,” says Glocker, “give an insight into the biological basis for caretaking behaviour by human beings. They provide a neurophysiological explanation for our impulse to look after anything resembling a baby.”

For the study, Glocker manipulated baby photos with a special image editing programme which produced, in addition to the original photo, portraits with lower and higher baby schema values. For example, the same baby was given bigger or smaller eyes or a round or narrow face. Women who had not had children themselves looked at these children's faces, and their brain activity was measured with the aid of functional magnetic resonance imaging.

As the baby schema content increased, the researchers discovered a corresponding increase in activity in the nucleus accumbens, which is a region of the brain already known as a reward centre and which mediates motivated behaviour seeking reward, triggers feelings of happiness and plays a role in drug addiction, among other things. In addition, further regions of the brain react to the baby schema, including areas involved in the processing of faces and in attention. The researchers assume that similar processes could take place in men's brains.

“Activating the reward centre could represent the neurophysiological mechanism by which the baby schema motivates caretaking behaviour,” says Glocker, “irrespective of the degree of kinship between child and beholder.”

reference: Glocker et al. (2009) – Baby schema modulates the brain reward system in nulliparous women. Published online before print May 18, 2009, doi: 10.1073/pnas.0811620106