A collaboration between cognitive biologists and social neuroscientists at University of Vienna solves this problem by integrating behavioral and psychological methods. They show that ravens observing a conspecific in a negative emotional state subsequently perform in a pessimistic manner on a judgment task. The results of this study have been published in the scientific journal Proceedings of the National Academy of Sciences of the United States of America. [read more]
Adriaense, J.E.C., Martin, J.S., Schiestl, M., Lamm, C. & Bugnyar, T.: Negative emotional contagion and cognitive bias in common ravens (Corvus corax). Proceedings of the National Academy of Sciences of the United States of America, DOI: doi.org/10.1073/pnas.1817066116