Repeated Witnessing of Conspecifics in Pain: Effects on Emotional Contagion

• Published in: PloS one Vol. 10; no. 9; p. e0136979
• Main Authors: Carrillo, Maria, Migliorati, Filippo, Bruls, Rune, Han, Yingying, Heinemans, Mirjam, Pruis, Ilanah, Gazzola, Valeria, Keysers, Christian
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10-09-2015; Public Library of Science (PLoS)
• Subjects: Animals; Behavior; Behavior, Animal; Brain research; Brain stimulation; Conspecifics; Development and progression; Emotions; Empathy; Freezing; Freezing level; Freezing Reaction, Cataleptic; Genetic aspects; Glucocorticoids; Inhibition (psychology); Male; Neurosciences; Pain; Pain - physiopathology; Physiological aspects; Rats; Rats, Long-Evans; Rodents; Stress; Studies; Yawning; Yawning behavior; Netherlands
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0136979

Witnessing of conspecifics in pain has been shown to elicit socially triggered freezing in rodents. It is unknown how robust this response is to repeated exposure to a cage-mate experiencing painful stimulation. To address this question, shock-experienced Observer rats repeatedly witnessed familiar Demonstrators receive painful footshocks (six sessions). Results confirm that Observers freeze during the first testing session. The occurrence of this behaviour however gradually diminished as the experimental sessions progressed, reaching minimal freezing levels by the end of the experiments. In contrast, the appearance and continuous increase in the frequency of yawning, a behavior that was inhibited by metyrapone (i.e,. a glucocorticoid synthesis blocker), might represent an alternative coping strategy, suggesting that the observer's reduced freezing does not necessarily indicate a disappearance in the affective response to the Demonstrator's distress.