In both humans and Bonobos, individuals responded to yawns of those who were not friends or kin with the same level of frequency. However, humans responded more quickly when they were yawning after a friend or family member, whereas the level of responsiveness in Bonobos did not change.
Researchers hypothesized that this data indicates that the two species have very similar empathic capabilities, though humans, unlike Bonobos, have a higher level of empathy towards those individuals with whom they are close. This difference is most likely due to a more complex emotional foundation (cognition, memories, etc.), whereas empathy in Bonobos is likely more species-based.