Physical Contact Promotes the Development of Emotional Contagion Between Mice.

The establishment and maintenance of strong affiliative relationships is fundamental for group cohesion and crucial for overall individual well-being. Empathy is considered a critical process for promoting attachment and the long-term stability of social bonds. However, it is unclear how different modalities of social communication contribute to the development of empathy. Physical contact between individuals, such as gentle touching, is a highly salient form of social communication. Despite mounting evidence that touch may be crucial for promoting social bonds, the role of touch in the development of empathy is currently not well understood. Animal models have become a powerful tool for the experimental manipulation and examination of empathy related behaviors such as emotional contagion. Here, we use the Tube Co-Occupancy Test (TCOT) to promote voluntary physical contact between mice and examine whether social, physical contact promotes emotional contagion of pain between mice. We found that repeated exposure to TCOT promoted the development of emotional contagion between mice. However, preventing physical contact in the TCOT assay also prevented the development of emotional contagion of pain. These results demonstrate that voluntary physical contact is a critical component in the formation of social bonding and emotional contagion in mice.