Yawning is more contagious for the young, study says

Yawning. We all do it and yet there's no set explanation for why we do it. Just as mysterious is that the act of yawning seems to be contagious. A new study looking at that issue has found that age might be a factor. (Via Blip.TV)
 
The study, one of the largest ever to focus on contagious yawning, was published online at PLOS ONE, and found that young people are more apt to "catch" a yawn than older people. 
 
328 participants were asked to watch a three-minute video of people yawning and to keep track of how many times they yawned. Of the 328 participants, 222 contagiously yawned. (Via YouTube /AsapSCIENCE)
 
While past research has linked empathy, time of day, and intelligence to yawning, the Duke University researchers found no such links.
 
USA Today spoke with one researcher not involved in the study who has found that "contagious yawning is most common among family members, followed by friends, acquaintances and then strangers."

But what benefits could there possibly be from studying yawning? 
 
Referring to autism and schizophrenia, a press release for the study said.  "A deeper understanding of contagious yawning could lead to insights on these diseases and the general biological functioning of humans." (Via EurekAlert)
 
As to why we actually yawn? Various heories exist, but one of the most widely held says yawning cools the brain.