A study conducted at the University of Wisconsin Department of Psychology examined the role pacifiers play in the psychological development of children.

UW psychology professor and lead author of the study Paula Niendenthal said inspiration for the study came from the question about whether pacifiers blocked social interactions to the extent that they would have a harmful effect on development.

“This idea led to a study of how prolonged pacifier use affected whether people mimic and develop emotional consequences,” Niendenthal said.

Niendenthal said the general idea behind the importance of mimicking is the fact that the action is a functional and active learning idea, allowing the body to recreate information it received through facial nerves that cause expressions and facial nerves that take messages to the brain.

Niendenthal said the department conducted three studies to further explore the idea.

In the first study, Niendenthal said researchers studied children of ages 6 and 7 and whether they could mimic faces when they looked at them. Results found boys who used pacifiers longer were less able to mimic faces, she said.

In the second study, Niendenthal said researchers asked college-age students to report on their pacifier use in childhood and relate the pacifier use to their scales of visible emotions. The longer boys used pacifiers, the lower their scores were regarding empathy, she said.

In the third study, Niendenthal said questionnaires were administered regarding the relationship between the length of pacifier use and levels of emotional intelligence. She said from this study, researchers found the longer boys used pacifiers, the lower they scored in ability to understand other peoples emotions.

Niendenthal said further research is needed for these findings.

She said society trains girls to expect to understand people’s emotions and be expressive emotionally, and because parents discuss and encourage emotions around girls much more than boys, the general result is boys are more vulnerable to social and developmental implications.

A UW statement said researchers found heavy pacifier use in childhood is tied to levels of emotional maturity found.

This is the first study to tie pacifiers with psychological development, the statement said.