I paced through the streets of Friday Harbor, a tourist town on San Juan Island which was empty of tourists. It was spring in 2014. The town, nestled around a ferry harbor at one end (I was waiting for my class’s ferry to arrive and had an hour to myself), was quiet and inviting, clear of the crowds I guessed would be there in only a month or two. I had just purchased a sandwich and snacks from a local shop and was looking for a place to eat. Ever the anti-social loner, I didn’t want to sit awkwardly by the docks while my classmates had their lunches. Instead, I made my way up the street and found a tiny park situated above the gleaming waters of Puget Sound. I took a seat on a bench and started unwrapping my food. I could feel the slight tingling sensation on my arms that meant I was slowly getting a sunburn, but I ignored it. I wouldn’t be out in the sun much longer and I wanted to enjoy it.
As I began my lunch, a group of crows fluttered down in various perches around the park. I had seen them all over town, individuals or small clumps of them traveling between buildings or scavenging around the streets, always wary of my approach. These ones seemed interested in me, though.
One crow flew down onto the grass and pavement in front of me, quite close. I watched it, curious. One-half of my unwrapped sandwich was on its paper on the bench beside me, the other half in my hands. The crow started clumsily hopping toward me, its gait uneven. Concerned, I leaned forward, but it hopped back again and started lurching across the grass. I noticed another crow flap down slightly behind and to the side of my bench. I ignored it and kept watching the odd hopping bird.
I twisted around after a few seconds to see where the other crows were and found that the other bird that had landed by my bench was suddenly several feet closer, eyes trained on my sandwich. I laughed quietly, starting to realize their game. I turned my head again to watch the hopping crow and then turned back a second time. As I had expected, the second crow was even closer to my food.
Laughing further, I picked up my sandwich. “I know what you guys are doing,” I told them cheerfully, “I’m not going to share this.” But that was a lie. Amused at their efforts to trick me out of my sandwich, I left a few small pieces of bread for them before I headed back to the ferry.
Of course, I can’t be sure that they were indeed trying to deceive me, but that was how it had appeared for all intents and purposes. Crows are known for sophisticated acts of trickery and planning, so this kind of deceptive teamwork could be within their realm of cognitive ability.
This kind of trick in the animal kingdom is an example of tactical deception. There are many forms of deception among animals, ranging from camouflage designed to make a leafy sea dragon look like seaweed to possums feigning death when predators have found them to tufted capuchins giving alarm calls when they have found food in order to keep it all for themselves (Wheeler 2009). This last example is also a form of tactical deception, in which animals purposefully use behavior they know others will misinterpret to give themselves some form of advantage.
I was reminded of the crows in Friday Harbor, Washington recently when I started watching Lie to Me, a television show based around the idea that deception in humans comes with visual cues. Deception in real life, among animals both human and nonhuman, is not so simple in reality, but it is an interesting topic nonetheless. When deceivers of social species are discovered they are often punished by society. When rhesus monkeys fail to report discovered food but that act is itself discovered, they become the subjects of increased aggression by their peers (Hauser 1992). In humans the social implications of cheating can be more diverse, ranging from ostracism to legal consequences.
One of the hottest debates in the field of animal behavior involving deception is exactly what function of the brain produces tactical deception. Deception is a sophisticated social ability, but just how sophisticated? Are the deceptive behaviors learned tricks involving manipulation of others’ behavior, or are the deceivers actually anticipating the knowledge in the minds of others? This latter option has a name: Theory of Mind. It is the ability to know that your peers also have minds which can contain knowledge, beliefs, and emotions. In humans, this ability develops around the age of four to six (there’s a good reason toddlers are so selfish: they can’t properly comprehend that others can think and feel!) (Wimmer and Perner 1983). Do any other animal species possess Theory of Mind?
So far, the debate continues. There has been a lot of potential evidence for Theory of Mind in dolphins, great apes, and corvid species (among others) but researchers are not yet able to say for certain if it is actually Theory of Mind they are displaying or just another form of learning (most alternative explanations involve the animals making inferences based on the behavior of others rather than representations of their mental states). Penn and Povinelli (2007) summarize the counter explanations for some of the examples of deception. Corvids (the group of birds containing crows, ravens, and jays) display complex food-caching behaviors depending on others. Some species will re-hide their food if a peer is watching, and can even remember which peer was the watcher. Thieves will not attempt to steal cached food if the one who originally hid it is present. Western scrub jays, specifically, will deploy additional measures to hide and re-hide their food if they are accomplished thieves themselves, suggesting they may be able to project their own experiences onto others (I am a thief, therefore this other bird could be a thief as well!).
Of course, the counterarguments all suggest that the caching behaviors could just be very sophisticated learned methods for keeping food safe. Even the scrub jays might have another reason for being more careful with their food if they are thieves (although the arguments against this ability seem weaker).
Since—so far—solid, widely accepted evidence for Theory of Mind hasn’t been shown in acts of deception, what could provide evidence of it? The most common way to nonverbally assess the presence of Theory of Mind in human children is to use a false belief task. Often this involves the subject watching someone else witness a desirable item being hidden. The witness then leaves the area and the item is either left alone or moved to a new location. The witness then returns and the subject must guess which location they will search for the item in (Suddendorf and Fletcher-Flinn 1999). If the subject has Theory of Mind then they will understand that the witness can have false beliefs as well as true ones, and so when the item has been moved the subject will guess that the witness will look for it in the original location.
This test has been carried out with some animals, with limited success. The most successful trials involved bottlenose dolphins who did pass with a significant margin, but there were too many confounding factors in the setup and methodology of the experiment to make strong conclusions (Pack and Herman 2006). Dolphins, like corvids, are also quite capable of deception. Diana Reiss, in her book The Dolphin in the Mirror, writes about a famous example: captive dolphins were trained to bring pieces of trash in their pool back to human handlers to help clean up. They would receive a fish reward for every piece of trash. One clever dolphin hid one large piece of plastic under a rock at the bottom of the pool and would bring back several small ripped strips from it during clean up times, receiving many treats at once. Her deception was eventually uncovered, probably to her dismay.
Could dolphins also be using a Theory of Mind to deceive others? This particular behavior could easily be based on other kinds of learning, but perhaps the dolphin did have an understanding that the humans assumed she was honestly bringing individual pieces of trash to them and did not know about the larger hidden piece.
So far, the evidence for corvids and dolphins displaying a Theory of Mind to guide their deceptive efforts is suggestive but inconclusive. Of course, researchers might be going about this the wrong way. Is it really necessary for an animal to have the same level of Theory of Mind as a human in order to be able to know that other animals can have knowledge and beliefs? Could there be orders of magnitude to Theory of Mind? It will only take further research to uncover the depths of this amazing cognitive ability.
And what about those crows back in Friday Harbor? When they were trying to trick me, did they understand that I possessed knowledge about where they were, where my sandwich was, and a belief that my sandwich would remain next to me (a belief they were trying to make false)? Certainly, they could determine the direction of my gaze and the focus of my attention. For now, I don’t really know the answer. Like many other mysteries, we must rely on science to reveal gradual small truths until a bigger picture is constructed.
Hauser, M. D. (1992). Costs of deception: Cheaters are punished in rhesus monkeys (Macaca mulatta). Proceedings of the National Academy of Science USA 89, 12137-12139.
Pack, A. A., & Herman, L. M. (2006). Dolphin Social Cognition and Joint Attention: Our Current Understanding. Aquatic Mammals 32(4), 443-460.
Penn, D. C., & Povinelli, D. J. (2007). On the lack of evidence that non-human animals possess anything remotely resembling a ‘theory of mind’. Philosophical Transactions of the Royal Society B 362, 731-744.
Reiss, Diana (2011). The Dolphin in the Mirror: Exploring Dolphin Minds and Saving Dolphin Lives. Mariner Books.
Suddendorf, T., & Fletcher-Flinn, C. M. (1999). Children’s Divergent Thinking Improves When They Understand False Beliefs. Creativity Research Journal 12(2), 115-128.
Wheeler, B. C. (2009). Monkeys crying wolf? Tufted capuchin monkeys use anti-predator calls to usurp resources from conspecifics. Proceedings of the Royal Society B 276, 3013-3018.
Wimmer, H., & Perner, J. (1983). Beliefs about beliefs: Representation and constraining function of wrong beliefs in young children’s understanding of deception. Cognition 13, 103-128.
Birding Information. Scrub Jay, La Purisima Mission, Lompoc, CA. “Western Scrub Jay.” <http://www.birdinginformation.com/birds/ravens-crows-magpies-jays/western-scrub-jay/>
San Juan Islands. Image 1. “Friday Harbor, San Juan Island.” <http://www.visitsanjuans.com/about-islands/friday-harbor-san-juan-island>
The Institute for Marine Mammal Studies. Dolphin Encounter Program. “Dolphin Programs.” <https://www.imms.org/dolphin_program.php>