6.5 Emotional Contagion

Emotional (or social) contagion is the capacity to “catch” another’s mood. For example, observing one individual in a sour mood may lead to the observer’s mood worsening. In most cases, emotional contagion is reflexive. You get startled and jump, I jump in response to your surprise or fear. You begin to cry, and I may tear up suddenly in an empathetic but contagious response to your sorrow.

Wataru Nakahashi and Hisashi Ohtsuki provide an explanation for the adaptive value of emotional contagion in their 2015 article, “When is emotional contagion adaptive?” After defining three reactive strategies (independent reaction, behavioral mimicry, and emotional contagion), the authors provide the following conditions in which emotional contagion is likely to evolve:

• When an organism’s observation of their environment (including other animals) is likely to include errors, and
• When observers only pay attention to less frequent, but often incredibly important, behavior.

Furthermore, they argue, emotional contagion is a component of social learning and may require the observed reactions of conspecifics in order for the reflexive response to express.

Most research into emotional contagion focuses on the contagion of fear or distress. As explained by Ana Pérez-Manrique and Antoni Gomila in their 2021 review article, the adaptive advantages of contagious fear are obvious. By rapidly responding to the fear of others, more members of a social group are likely to escape predators and other threats. Likewise, parental care may rely upon the contagion of offspring distress to respond quickly to the needs of their young.

This begs the question – are only emotions connected to the fight or flight system contagious?

Do Dogs Laugh?

In 2001, Patricia Simonet provided evidence at the Animal Behavior Society’s annual conference for laughter in dogs. After analyzing recordings of dog-dog play, she found a specific “forced, breathy exhalation” that occurred only during play. This vocalization did not occur in any other forms of interaction.

Later, she tested whether playback of recorded “laughs” could influence emotional distress in shelter dogs. In 2005, she presented data at the International Conference on Environmental Enrichment that suggested shelter dogs experienced a decrease in barking and other stress behaviors during the playback condition.

More than 10 years after Simonet’s passing, the ECHOS Lab at Boise State University, once again began to explore the canine play pant. While asking the questions, “Do dogs laugh? Can humans elicit this response?” the team used audio and video recordings of human-dog play to validate Simonet’s findings. Below is a short video demonstrating the difference between Toldi’s (a labradoodle) play pant and his normal, resting pant.

The potential for emotional contagion between humans and other species speaks to the importance of an evolutionary perspective when exploring human behavior.