Where are you calling from? <a href=" http://www.jgwilson.co.uk/olanzapine-joint-pain.pdf ">zyprexa effects</a> In order to examine yawn contagion, the scientists looked at two factors in chimps: their age and their emotional closeness to the person yawning. In all, they examined 33 orphaned chimpanzees, including 12 infants that were between one and four years and 21 juveniles that were between 5 and 8 years. During trials, a human repeatedly either yawned, gaped or nose-wiped during one session and then followed it by three sessions where these key behaviors weren't used.  Each set of trials was performed by an unfamiliar human and a familiar human.