Skip to main content

See also:

Intelligence of crows, jealousy of dogs, and first graders

In Aesop’s fable about the crow and the pitcher, a thirsty bird happens upon a vessel of water, but when he tries to drink from it, he finds the water level out of his reach. Not strong enough to knock over the pitcher, the bird drops pebbles into it — one at a time — until the water level rises enough for him to drink his fill. You may wish to take a look at a new study, "Modifications to the Aesop's Fable Paradigm Change New Caledonian Crow Performances," published online July 23, 2014 in the journal PLOS ONE.

Intelligence of crows, jealousy of dogs, and first graders.
Photo by Isaac Brekken

Highlighting the value of ingenuity, the fable demonstrates that cognitive ability can often be more effective than brute force. It also characterizes crows as pretty resourceful problem solvers. New research conducted by the University of California - Santa Barbara's Corina Logan, with her collaborators at the University of Auckland in New Zealand, proves the birds’ intellectual prowess may be more fact than fiction. Her findings, supported by the National Geographic Society/Waitt Grants Program, appear July 23, 2014 in the scientific journal PLOS ONE.

Logan is lead author of the paper, which examines causal cognition using a water displacement paradigm. “We showed that crows can discriminate between different volumes of water and that they can pass a modified test that so far only 7- to 10-year-old children have been able to complete successfully. We provide the strongest evidence so far that the birds attend to cause-and-effect relationships by choosing options that displace more water.”

Logan, a junior research fellow at UCSB’s SAGE Center for the Study of the Mind, worked with New Caledonian crows in a set of small aviaries in New Caledonia run by the University of Auckland. “We caught the crows in the wild and brought them into the aviaries, where they habituated in about five days,” she said, according to the July 23, 2014 news release, "Smarter than a first-grader?" Keeping families together, they housed the birds in separate areas of the aviaries for three to five months before releasing them back to the wild.

Getting individual crows into the testing room proved to be an immediate challenge

“You open the testing room door and then open the aviary door, with the idea that the bird you want is going to fly through into the testing room,” she said, according to the news release. But with four birds in an aviary, directing a particular test subject is tricky at best.

“So I thought, let’s pretend the sky’s the limit and I can train them to do whatever I want,” Logan explained in the news release. “I started by pointing at the one I wanted and continuing to point until he or she flew out. I got to the point where I could stand outside the aviary and point at the one I wanted and it would fly out while the other birds stayed put.”

Two birds in particular — 007 and Kitty — became so well trained that Logan had only to call them by name and they’d fly into the testing room

The testing room contained an apparatus consisting of two beakers of water, the same height, but one wide and the other narrow. The diameters of the lids were adjusted to be the same on each beaker. “The question is, can they distinguish between water volumes?” Logan said in the news release. “Do they understand that dropping a stone into a narrow tube will raise the water level more?”

In a previous experiment by Sarah Jelbert and colleagues at the University of Auckland, the birds had not preferred the narrow tube. However, in that study, the crows were given 12 stones to drop in one or the other of the beakers, giving them enough to be successful with either one.

“When we gave them only four objects, they could succeed only in one tube — the narrower one, because the water level would never get high enough in the wider tube; they were dropping all or most of the objects into the functional tube and getting the food reward,” Logan explained, according to the news release. “It wasn’t just that they preferred this tube, they appeared to know it was more functional.” However, she noted, we still don’t know exactly how the crows think when solving this task. They may be imagining the effect of each stone drop before they do it, or they may be using some other cognitive mechanism. “More work is needed,” Logan said, according to the news release.

Logan also examined how the crows react to the U-tube task

Here, the crows had to choose between two sets of tubes. With one set, when subjects dropped a stone into a wide tube, the water level raised in an adjacent narrow tube that contained food. This was due to a hidden connection between the two tubes that allowed water to flow. The other set of tubes had no connection, so dropping a stone in the wide tube did not cause the water level to rise in its adjacent narrow tube.

Each set of tubes was marked with a distinct color cue, and test subjects had to notice that dropping a stone into a tube marked with one color resulted in the rise of the floating food in its adjacent small tube. “They have to put the stones into the blue tube or the red one, so all you have to do is learn a really simple rule that red equals food, even if that doesn’t make sense because the causal mechanism is hidden,” said Logan in the news release.

As it turns out, this is a very challenging task for both corvids (a family of birds that includes crows, ravens, jays and rooks) and children

Children ages 7 to 10 were able to learn the rules, as Lucy Cheke and colleagues at the University of Cambridge discovered in 2012. It may have taken a couple of tries to figure out how it worked, Logan noted, but the children consistently put the stones into the correct tube and got the reward (in this case, a token they exchanged for stickers). Children ages 4 to 6, however, were unable to work out the process. “They put the stones randomly into either tube and weren’t getting the token consistently,” she said, according to the news release. Recently, Jelbert and colleagues from the University of Auckland put the New Caledonian crows to the test using the same apparatus the children did. The crows failed.

So Logan and her team modified the apparatus, expanding the distance between the beakers. And Kitty, a six-month-old juvenile, figured it out. “We don’t know how she passed it or what she understands about the task,” Logan said in the news release, “so we don’t know if the same cognitive processes or decisions are happening as with the children, but we now have evidence that they can. It’s possible for the birds to pass it. What we do know is that one crow behaved like the older children, which allows us to explore how they solve this task in future experiments,” she continued.

Research on causal cognition using the water displacement paradigm is only beginning to get at what these crows know about solving problems. This series of experiments shows that modifying previous experiments is useful for gaining a deeper understanding. The research on the crows is part of a larger project Logan is working on to compare the cognitive powers of crows with those of grackles.

“So far, no smaller-brained species have been tested with the tests we use on the crows, and grackles are smaller-brained,” she said, according to the news release. “But they’re really innovative. So they may have a reason to pay attention to causal information like this.” The next research phase will begin next month, after the grackles’ breeding season ends and they are ready to participate.

Jealousy in dogs

You also may be interested in another noteworthy study, "Jealousy in Dogs," published online July 23, 2014 also in the journal PLOS ONE. It's commonly assumed that jealousy is unique to humans, partially because of the complex cognitions often involved in this emotion, notes that study's abstract. However, from a functional perspective, one might expect that an emotion that evolved to protect social bonds from interlopers might exist in other social species, particularly one as cognitively sophisticated as the dog.

If you take a look at the abstract of that study, you can see how the researchers adapted a paradigm from human infant studies to examine jealousy in domestic dogs. The results of the study found that dogs exhibited significantly more jealous behaviors (for example, snapping, getting between the owner and object, pushing/touching the object/owner) when their owners displayed affectionate behaviors towards what appeared to be another dog as compared to nonsocial objects. The study's based on a hypothesis, but the results of that research do lend support to the hypothesis that jealousy has some “primordial” form that exists in human infants and in at least one other social species besides humans.

This will not surprise most dog owners: Dogs can act jealous, finds a new study from the University of California, San Diego. Darwin thought so, too

Emotion researchers have been arguing for years whether jealousy requires complex cognition. And some scientists have even said that jealousy is an entirely social construct – not seen in all human cultures and not fundamental or hard-wired in the same ways that fear and anger are.

The current study, "Jealousy in Dogs," published in PLOS ONE by Univeristy of California, San Diego psychology professor Christine Harris and former honors student Caroline Prouvost – is the first experimental test of jealous behaviors in dogs. The findings support the view that there may be a more basic form of jealousy, which evolved to protect social bonds from interlopers.

Harris and Prouvost show that dogs exhibit more jealous behaviors, like snapping and pushing at their owner or the rival, when the owner showed affection to what appeared to be another dog (actually a stuffed dog that barked, whined and wagged its tail). Dogs exhibited these behaviors more than if the same affection was showered on a novel object and much more than when the owner's attention was simply diverted by reading a book.

"Our study suggests not only that dogs do engage in what appear to be jealous behaviors but also that they were seeking to break up the connection between the owner and a seeming rival," Harris said, according to the July 23, 2014 news release, Dog jealousy: Study suggests primordial origins for the 'green-eyed monster'. "We can't really speak to the dogs' subjective experiences, of course, but it looks as though they were motivated to protect an important social relationship."

Since there had been no prior experiments on dog jealousy, the researchers adapted a test used with 6-month-old human infants. They worked with 36 dogs in their own homes and videotaped the owners ignoring them in favor of a stuffed, animated dog or a jack-o-lantern pail. In both these conditions, the owners were instructed to treat the objects as though they were real dogs – petting them, talking to them sweetly, etc. In the third scenario, the owners were asked to read aloud a pop-up book that played melodies. Two independent raters then coded the videos for a variety of aggressive, disruptive and attention-seeking behaviors.

Dogs were about twice as likely to push or touch the owner when the owner was interacting with the faux dog (78 percent) as when the owner was attending to the pail (42 percent). Even fewer (22 percent) did this in the book condition. About 30 percent of the dogs also tried to get between their owner and the stuffed animal. And while 25 percent snapped at the "other dog," only one did so at the pail and book.

Did the dogs believe the stuffed animal was a real rival?

Harris and Prouvost write that their aggression suggests they did. They also cite as additional evidence that 86 percent of the dogs sniffed the toy dog's rear end during the experiment or post-experiment phase.

The majority of research on the topic, Harris said, is on jealousy between human mates. But a great deal of jealousy in humans concerns siblings, friends and even close co-workers. Also, the first signs of human jealousy are seen in babies and young children, she said, suggesting both that the emotion may have evolved with siblings competing for parental resources and that we are "wired up" for it.

Understanding jealousy is important, the researchers write, because it is an emotion with far-reaching psychological and social consequences. For example, it often emerges as the third leading cause of non-accidental homicide. "Many people have assumed that jealousy is a social construction of human beings – or that it's an emotion specifically tied to sexual and romantic relationships," Harris said, according to the news release. "Our results challenge these ideas, showing that animals besides ourselves display strong distress whenever a rival usurps a loved one's affection."