Bonobos also catch a yawn like humans

Yawning can be as contagious between bonobos as it is among people, a new study has found, suggesting that the apes are capable of human-like empathy.
Researchers directly compared the 'yawn contagion' effect between humans and our closest evolutionary cousins bonobos.
They directly compared empathic abilities and found that a close relationship between individuals is more important to their empathic response than the fact that individuals might be from the same species.
The transmission of a feeling from one individual to another, something known as 'emotional contagion,' is the most basic form of empathy.
"Yawn contagion is one of the most pervasive and apparently trivial forms of emotional contagion," said Elisabetta Palagi from the University of Pisa in Italy.

Humans and bonobos are the only two species in which it has been demonstrated that yawn contagion follows an empathic trend, being more frequent between individuals who share a strong emotional bond, such as friends, kin, and mates.

Researchers sought to directly compare the two species. Over the course of five years, they observed both humans and bonobos during their everyday activities and gathered data on yawn contagion by applying the same ethological approach and operational definitions.
Two features of yawn contagion were compared: how many times the individuals responded to others' yawns and how quickly.
Intriguingly, when the yawner and the responder were not friends or kin, bonobos responded to others' yawns just as frequently and promptly as humans did.

This means that the assumption that emotional contagion is more prominent in humans than in other species is not necessarily the case, researchers said.
However, humans did respond more frequently and more promptly than bonobos when friends and kin were involved, probably because strong relationships between humans are built upon complex and sophisticated emotional foundations linked to cognition and memories.
In this case, the positive feedback linking emotional affinity and the mirroring process seems to spin faster in humans than in bonobos.
In humans, such over-activation may explain the potentiated yawning response and also other kinds of unconscious mimicry response, such as happy, pained, or angry facial expressions.

The study suggests that differences in levels of emotional contagion between humans and bonobos are attributable to the quality of relationships shared by individuals.
When the complexity of social bonds, typical of humans, is not in play, Homo sapiens climb down the tree of empathy to go back to the understory which we share with our ape cousins.
The research was published in the journal PeerJ.