Editing Corvidae (section)

==== Empathy-emotional contagion ====
[[Emotion]] contagion refers to the [[emotional state]] matching between individuals. Adriaense et al. (2018) used a [[cognitive bias|bias]] paradigm to quantify [[emotional valence]], which along with [[emotional arousal]], define emotions.<ref>{{Cite journal|last1=Edgar|first1=Joanne L.|last2=Nicol|first2=Christine J.|date=December 2018|title=Socially-mediated arousal and contagion within domestic chick broods|journal=Scientific Reports|volume=8|issue=1|pages=10509|doi=10.1038/s41598-018-28923-8|issn=2045-2322|pmc=6043517|pmid=30002482|bibcode=2018NatSR...810509E}}</ref> They manipulated the positive and negative affective states in the demonstrator ravens, which showed significantly different responses to the two states: behaving pessimism to the negative states, and optimism to the positive states. Then, the researchers trained another observer raven to first observe the demonstrator's responses. The observer raven was then presented with ambiguous stimuli. The experiment results confirmed the existence of negative emotional contagions in ravens, while the positive emotional contagion remained unclear. Therefore, ravens are capable of both discerning the negative emotions in their conspecifics and showing signs of empathy.<ref>{{Cite journal|last1=Adriaense|first1=Jessie E. C.|last2=Martin|first2=Jordan S.|last3=Schiestl|first3=Martina|last4=Lamm|first4=Claus|last5=Bugnyar|first5=Thomas|date=4 June 2019|title=Negative emotional contagion and cognitive bias in common ravens (''Corvus corax'')|journal=Proceedings of the National Academy of Sciences|volume=116|issue=23|pages=11547–11552|doi=10.1073/pnas.1817066116|issn=0027-8424|pmc=6561263|pmid=31110007|bibcode=2019PNAS..11611547A |doi-access=free}}</ref>