PHILADELPHIA (CBS Philadelphia) – Women are twice as likely to yawn as men because they feel more empathy, according to researchers.

The study observed more than 1,400 yawns over a five year period.

Researchers say none of the participants knew they were being watched.

The study found that rates of yawn ‘contagion’ were considerably lower between acquaintances than between friends.

Because there is growing evidence that yawn contagion is an empathy-based phenomenon, researchers say they expect that female bias in the empathic abilities reflects on a gender skew in the responsiveness to others’ yawns.

Researchers write in the journal Royal Society Open Science, “The completely new finding of this study is that under natural conditions women from our population sample contagiously yawned at significantly higher rates than men.”

“The literature examining sex differences in empathy-based behaviors is scarce but still suggests that—compared with males—females are more sensitive to others’ emotions and more inclined to behave prosocially.”