Baby smile gives mum a natural high

A baby's smile not only brightens a mother's day, but triggers a response in the brain that leads to a natural high, according to new research. Scientists have found that first-time mothers display the brain activity associated with reward when they see their new babies smile. A study of 28 new mums by Texas Children's Hospital found that the reaction in the brain depended on the expression on the babies' faces. Mothers were shown images of babies aged between five and ten months, with the highest level of brain activity noted when participants were shown pictures of their own smiling child.

Neutral or sad expressions triggered the least reaction, with scientists surprised that sad faces didn't carry a response of its own.

"The strongest activation was with smiling faces," said lead researcher Dr Lane Strathearn: "We were expecting a different reaction with sad faces."

He added: "Understanding how a mother responds uniquely to her own infant, when smiling or crying, may be the first step in understanding the neural basis of mother - infant attachment."

In describing the reaction, Dr Strathearn concluded that the activated areas of the brain are also associated with drug addiction, suggesting to mothers that "it may be that seeing your own baby's smiling face is like a 'natural high'".