Ravens Know They're Being Watched: Bird Brain Theory of Mind
Many researchers and people interested in the behavior of nonhuman animals (animals) wonder what's happening in their heads and whether they possess what's called a theory of mind (TOM). Briefly, a theory of mind refers to "the ability to attribute mental states — beliefs, intents, desires, pretending, knowledge, etc. — to oneself and others and to understand that others have beliefs, desires, intentions, and perspectives that are different from one's own."
Historically, it's been suggested that only humans are cognitively and emotionally capable of having a TOM, end of story. But slowly, this brand of speciesism -- placing humans above and separate from other animals -- has changed as comparative data on other animals are collected. Now, some people believe that at least chimpanzees possess a theory of mind (for comparative data discussed in popular media please click here and for more academic studies and discussions please click here). However, other researchers are asking, why stop there, what about other animals, including birds?
Along these lines, a new study on ravens shows that these big-brained and smart and emotional birds might also possess a theory of mind. In an excellent study published in Nature Communications by Thomas Bugnyar and his colleagues called "Ravens attribute visual access to unseen competitors," data are presented that strongly suggest that ravens also possess a theory of mind. This study predictably received attention by media around the world, and the entire essay is available online.
Let me briefly summarize the findings of this landmark research. The abstract for this study reads, "Here, we show that ravens Corvus corax take into account the visual access of others, even when they cannot see a conspecific. Specifically, we find that ravens guard their caches against discovery in response to the sounds of conspecifics when a peephole is open but not when it is closed. Our results suggest that ravens can generalize from their own perceptual experience to infer the possibility of being seen. These findings confirm and unite previous work, providing strong evidence that ravens are more than mere behavior-readers." An essay called "Ravens can imagine being spied on, study finds" nicely lays out what the experimental protocol involved.
Over a six-month period scientists studied 10 ravens that had been raised in captivity. The birds were placed in adjoining rooms divided by a window that was initially left uncovered so one raven could watch while the other was given food to hide. Researchers then covered the window, but left a peephole in it that the birds were taught they could see and be seen through. Once this basic training was in place, the scientists played a recording of raven sounds while a bird was in the process of storing its food. Only when the peephole was open, however, did the raven take extra care to hide its food. If the peephole remained closed, the bird – even when raven noises were audible – somehow concluded that it could not be spied upon.
In the same article researcher Thomas Bugnyar is quoted as saying, "This strongly suggests that ravens make generalisations based on their experience, and do not merely interpret and respond to behavioural cues from other birds."
What I really like about this study is the care with which the researchers consider alternative explanations and effectively challenge those who think that only humans and perhaps chimpanzees possess a theory of mind. There really is no reason to assume that ravens and other birds haven't evolved this cognitive capacity, nor that other animals should be excluded from the theory of mind arena. We know that crows display amazing and unanticipated cognitive skills and emotional capacities (please see, for example, essays published in "Avian Einsteins" by Psychology Today writers John Marzluff and Tony Angell) and I've argued that we might also find evidence for a theory of mind in the social play of dogs and other animals. Indeed, there is a lot of room for more comparative research on a wide array of animals in various social situations. The present study on ravens shows how clever experimental designs and careful observations can help shed light on questions about who possesses a theory of mind and why this capacity has evolved. Being a birdbrain isn't all the bad after all.
Please stay tuned for more on this sort of research and other investigations into the cognitive and emotional worlds of animals. It seems like every day we're learning more and more about the exceptional lives of numerous animals, and closing the door with narrow minded human exceptionalism (some call it human arrogance) based on unstudied preconceptions and prejudices is unwarranted by comparative research on a wide variety of animals.
Marc Bekoff's latest books are Jasper's Story: Saving Moon Bears (with Jill Robinson), Ignoring Nature No More: The Case for Compassionate Conservation, Why Dogs Hump and Bees Get Depressed: The Fascinating Science of Animal Intelligence, Emotions, Friendship, and Conservation, Rewilding Our Hearts: Building Pathways of Compassion and Coexistence, and The Jane Effect: Celebrating Jane Goodall (edited with Dale Peterson). (Homepage: marcbekoff.com; @MarcBekoff)