Parent alert: Pacifiers may be harmful to your sons’ emotional aptitude. Researchers have noted that the ability to mimic facial expressions helps us understand the emotions of others. Now, a new study of French and American youth has found that boys (but not girls) who spent more of their early years using pacifiers during the day—thereby limiting facial expressiveness—grew up to have less emotional aptitude, including less ability to mimic facial expressions and understand others’ perspectives. Thumb-sucking was not associated with reduced emotional aptitude.

Niedenthal, P. et al., “Negative Relations between Pacifier Use and Emotional Competence,” Basic and Applied Social Psychology (September/October 2012).