ANIMALS - As chimpanzees grow, so does yawn contagion

As sanctuary-kept chimpanzees grow from infant to juvenile, they develop increased susceptibility to human yawn contagion, possibility due to their increasing ability to empathize, says a study published October 16, 2013, in the open-access journal PLOS ONE by Elainie Madsen and colleagues from Lund University ...

http://phys.org/news/2013-10-chimpanzees-contagion.htm