By Dr. Becker
Scientists have long been reluctant to attribute empathy to animals other than humans. But this seemingly complex “human” trait has been demonstrated in a number of species, from dogs, dolphins and elephants to, now, rodents.
One of the latest studies on the topic of rodent empathy was conducted by researchers at Yerkes National Primate Research Center at Emory University.
They believe the secret to empathic behavior is not as complex as was once believed. Instead, it may have its roots in the hormone oxytocin, also known as the “love hormone.”
Prairie Voles Engage in Empathic Behavior and Console Each Other
One of the hallmarks of empathy is the capacity to console another being in a time of need or distress. Such behavior is widely displayed among humans and great apes, but it’s becoming increasingly apparent that other species console each other as well.
Take prairie voles, which are rodents that form long-term monogamous pairs and raise their offspring together. Emory University researchers conducted an experiment in which prairie voles were isolated from other familiar voles, then exposed to a stressor.
When the prairie voles were reunited, the non-stressed voles licked and groomed the animals that had been stressed, but this consoling behavior only occurred among prairie voles that were familiar with each other before being separated.
The researchers also blocked oxytocin in the brains of some of the animals, which caused the consoling behavior to stop.
Study co-author Larry Young, director of the Silvio O. Conte Center for Oxytocin and Social Cognition at Emory University, told Discovery News, “Many complex human traits have their roots in fundamental brain processes that are shared among many other species.”1 The researchers concluded:2
“Here, we provide empirical evidence that a rodent species … greatly increases partner-directed grooming toward familiar conspecifics (but not strangers) that have experienced an unobserved stressor, providing social buffering.
Prairie voles also match the fear response, anxiety-related behaviors, and corticosterone increase of the stressed cagemate, suggesting an empathy mechanism.”
Rats Also Show Empathy
If a rat is given the choice of eating a chocolate treat or freeing a trapped cage mate, which do you think he’ll choose? In a study published in 2011, researchers designed an experiment to answer this question and reveal if rats display so-called “pro-social behavior” that may be driven by empathic concern for another.3
To test this, they placed a free rat in an arena with a cage mate trapped in a restrainer. The free rat learned how to intentionally and quickly open the restrainer to set the cage mate free. They did not, by the way, open empty restrainers or those containing objects.
To put the rats further to the test, the researchers then gave them the choice of freeing a cage mate or opening a restrainer containing chocolate. Then, the rats opened both restrainers and typically shared the chocolate.
“Thus, rats behave pro-socially in response to a conspecific’s distress, providing strong evidence for biological roots of empathically motivated helping behavior,” the researchers noted.
Birds Show Empathic Behaviors, Too
Birds display many signs that they, too, experience empathy. For instance, research has shown that flock members experience an increase in heart rate when a member of their group experiences a conflict, which suggests they all experience the distress.4
Rooks also engage in a specific behavior, bill twining, with a social partner following a conflict, which suggests the birds may be consoling one another.5 Ravens have also shown evidence of empathy. Writing in the journal PLOS One, researchers concluded:6
“Our findings suggest that in ravens, bystanders may console victims with whom they share a valuable relationship, thus alleviating the victims' post-conflict distress. Conversely victims may affiliate with bystanders after a conflict in order to reduce the likelihood of renewed aggression.
These results stress the importance of relationship quality in determining the occurrence and function of post-conflict interactions, and show that ravens may be sensitive to the emotions of others.”
Contagious Yawning: A Measure of Empathy
Yawning in response to someone else’s yawn is thought to show a capacity for empathy.7 Chimpanzees display contagious yawning in the presence of familiar chimpanzees, as do pet dogs in the presence of humans.
Last year, research also revealed the budgerigar (budgies, also known as parakeets) experience contagious yawning, which was the first evidence of the phenomenon in a non-mammalian species.8
A 2014 study published in PLOS One also found that wolves are capable of yawn contagion and the frequency increases depending on the level of emotional proximity.9
As the research continues to accumulate, it appears empathy may exist even without complex cognition and the “basic building blocks of empathy might be present in a wide range of species.”10