Seeing someone else suffer a big disappointment can have a pretty damaging effect on your own morale. That’s definitely the case with people—and it may be true for ravens, too.
New research suggests that, like humans and many other mammals, common ravens (Corvus corax) can read and internalize the emotional states of others. In the study, published today in the journal PNAS, ravens watch their friends grapple with a frustrating task in which they’re denied a tasty treat. Though the onlookers aren’t deprived of anything, they then seem to mirror their partners’ discontent, and start behaving pessimistically themselves.
Unlike people, ravens can’t speak freely about their emotional distress. But these results hint at the tantalizing possibility that humans aren’t alone in their interconnectedness, and could provide early evidence of something akin to empathy in birds.
“This paper is a tremendous step forward in being able to understand the evolutionary roots of empathy,” says Kaeli Swift, an animal behaviorist and corvid expert at the University of Washington who was not involved in the study. “I think it would be too far to say that [this paper shows] ravens are empathetic…but this work could be foundational in eventually arriving at that conclusion.”
Showing that non-human animals have empathy—the ability to understand and share the feelings of others—is no easy task. A big part of the challenge is obvious: Researchers can’t ask their subjects how they’re feeling, says Stephanie Preston, a neuroscientist studying emotion and behavior at the University of Michigan who was not involved in the study.
But some researchers argue that empathy can be broken down and tested through its more manageable components. For instance, you can’t have empathy without emotional contagion, or the tendency of the feelings and behaviors of an emotional reaction to hop from individual to individual even in the absence of what triggered them. Emotional contagion is, in a sense, a way to experience by proxy—and it can come with serious perks.
“This gives you the ability to learn information about something without having to experience it yourself,” Preston says. “There’s an advantage to not having to experience pain, or realize food makes you sick, or see that someone is threatening...it can also give you the information you need to provide help to another in distress. It’s an efficient way to learn in a social environment.”
Emotional contagion is a fixture of the human experience, but it’s also been demonstrated in other species, including rats and pigs, thought to be both clever and social. Though ravens have both these qualities in spades, no one had yet investigated whether these black-feathered birds could mirror the feelings of their friends. So a team of researchers led by Jessie Adriaense, a cognitive biologist at the University of Vienna, put a group (technically, an “unkindness”) of eight ravens raised at the Haidlhof Research Station in Austria to the test.
The researchers first sorted the most buddy-buddy birds into pairs. Then, one member of each raven duo, dubbed the “observer,” was placed in front of a closed, unfamiliar box—an ambiguous situation designed to probe the bird’s baseline emotional state. While an optimistic raven may eagerly toy with the container, expecting a reward, a pessimistic bird would more likely to regard it with skepticism. At the start of the experiment, the ravens curiously pecked at the box after only momentary hesitation.
Then, each observer raven looked on as its partner bird, the “demonstrator,” was emotionally manipulated by a scientist. Demonstrator ravens were shown two different food items of different appeal: scrumptious morsels of dried dog food and an unappealing nubbin of raw carrot. Then, a researcher took one food away and handled the remaining treat as if the bird was about to be fed. Those left ogling the kibble behaved enthusiastically, while those saddled with the unappetizing vegetable quickly lost interest. Though the spectating ravens couldn’t see the foods themselves, they remained privy to their friends’ reactions.
Immediately after watching this ordeal play out, each observer raven was presented once again with a mystery box. Not much changed for the birds who had just seen their friends zealously react to kibble. But the ravens who had witnessed their partners’ carroty chagrin waited much longer than before to start tinkering with the box—as if they had already resigned themselves to disappointment. (The birds later switched roles so that each raven in the study got to experience its own emotional rollercoaster.)
It’s not entirely clear why the effects of pessimism were stronger, but this finding isn’t entirely surprising, says Loma Pendergraft, a corvid cognition expert at the University of Washington who was not involved in the study. After all, there’s probably an evolutionary advantage to being a little more sensitive to negative outcomes. “If something is ambiguous...it’s better to tend towards caution, because the potential cost could include death,” he says.
But it seems something about the reactions of jilted demonstrators was, in fact, contagious. Had their partners “caught” their disillusionment?
It’s possible, but the study can’t guarantee that infectious element was emotion, says Jennifer Vonk, a cognitive psychologist at Oakland University who was not involved in the study. The researchers weren’t able to test the emotional state of the demonstrator ravens, making it tough to confirm if the observers were actually picking up on feelings, or a set of behaviors associated with them. Behaviors, too, can be contagious—just step into a room full of people and yawn.
Still, in many cases, emotions tend to come packaged up with a reliable set of behaviors, Preston says. “Each species has its own repertoire of behaviors that are common...you have to start somewhere.”
Going from emotional awareness to empathy remains a big jump, however. One crucial part of the equation that still needs to be addressed is whether infectious feelings come paired with concern and care for another individual in distress, Preston says. For that, an observer bird may be expected to soothe a disappointed demonstrator. (There is, however, separate evidence that ravens are capable of consoling and reconciling with each other after fights.)
None of that takes away from how exciting this find is, she adds—especially in birds. “These building blocks of empathy are present in diverse species,” she says. “Empathy is not something that defines us as humans. There is a long evolutionary history leading up to our ability to empathize.”