Strathearn, L. et al. (2008)
What's in a Smile? Maternal Brain Responses to Infant Facial Cues
Pediatrics 122, 40-51

  • This study used magnetic resonance imaging to investigate which regions of a mother’s brain are stimulated by her infant’s facial expressions.
  • Twenty-six first-time mothers were enrolled in the study and their babies were filmed in both “happy” and “sad” situations when they were seven months old. The film was used to generate still photos of each baby with a variety of expressions.
  • Three months later each mother completed a questionnaire about her relationship with her infant. Her brain activity was then monitored when she was shown photos of her own and other babies with happy, neutral and sad expressions.
  • Intense brain activity in areas associated with reward was observed when mothers were shown photos of their own smiling babies.
  • All photos of crying babies elicited intense emotional responses, but these were strongest with each mother’s own infant.
  • The stimulation of reward pathways in the brain by the sight of a mother’s own happy infant may help the development of maternal attachment.