Now researchers at Baylor College of Medicine have found that a baby's smile increases blood flow to a reward center in the mother's brain.
The study, in the journal Pediatrics, said that mothers looking at baby pictures showed a marked reaction whenever they saw their own child, especially if her baby was smiling.
Brain scans of the mothers showed activity in areas associated with the neurotransmitter dopamine, giving them a sensation of pleasure. The reaction was reduced if her child had a neutral or sad expression and was virtually absent with pictures of other babies.
