They can count, solve Aristotle’s logic puzzles and appreciate Impressionist art. Don’t underestimate the flying rat
FROM the piazzas of Venice to the sidewalks of New York City, the same refrain appears on signs the world over: “Do Not Feed the Pigeons!” “We just see them as a nuisance, flocking around McDonald’s and pecking all the French fries,” says , who has studied pigeons for more than three decades.
It wasn’t always this way. Not so long ago, we stuffed Columba livia specimens for display in military museums, honouring them for their brave flights transporting messages across enemy territory. to help him hone his theory of natural selection, and was dazzled by their charms. Before a visit from his friend the geologist Charles Lyell, Darwin wrote: “I will show you my pigeons! Which is the greatest treat, in my opinion, which can be offered to [a] human being.”
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Perhaps it’s high time to return those laurels. In addition to their well-known navigational expertise, it is now becoming clear that pigeons are capable of many impressive mental feats, in areas as diverse as memory, mathematics and art appreciation. The “flying rat” may even be able to outwit certain primates.
Urban pest or misunderstood genius? (Image: Plainpicture)
Pigeons probably owe some of their smarts to us. Humans first domesticated pigeons about 5000 years ago, breeding them for food and use as messengers. The pigeons seen roaming the streets today are the descendants of those domesticated birds. But even before we started nurturing them, pigeons were probably hanging around us, sheltering in our ancient dwellings and pecking at the plentiful grain in our fields.
Animals that have hitched themselves to human civilisations, such as dogs and rats, generally share certain features. They tend to be bolder than their wild counterparts. They also become generalists: rather than living in a well-defined ecological niche like a pine forest or a mountaintop, they have followed us into urban landscapes around the globe. To do so, their mental machinery had to become flexible. “Animals that are able to adapt to living with humans show a larger degree of cognitively complex behaviours,” says Güntürkün, who is at Ruhr University Bochum in Germany.
Those same abilities make pigeons great research subjects. It helps that they are widely available, inexpensive and easy to care for. “Most importantly, they have the attitude of a civil servant,” Güntürkün says. “You give them a job and for a bit of grain they’ll work for hours.”
The famed US behaviourist B. F. Skinner was one of the first scientists to notice these qualities. He became interested in the birds while training them to guide bombs for a secret second world war project. The project never came to fruition, but Skinner went on to establish a pigeon lab at Harvard University. Much as Darwin’s pigeons had shaped his theory of evolution, Skinner relied on his birds as he developed his theory of operant conditioning – the idea that behaviour is shaped by positive “reinforcement” from rewards and negative reinforcement from punishment.
As important as they were, such mostly revealed bland, reflexive behaviours, says , who studies animal cognition at the University of Otago in New Zealand. “That was probably partly responsible for our perception that pigeons are not terribly bright animals,” he says.
It’s a view Colombo once shared. He began his career in the US working with monkeys. When he moved to New Zealand, he didn’t have access to a primate lab, so he reluctantly switched to pigeons. “I’d be lying if I didn’t say I had a dim view of them,” he says. That opinion didn’t last long, however. “I turned around 180 degrees. They’re fantastic animals to work with.” More than 20 years on, he is still extolling their virtues.
Those virtues include a phenomenal memory; pigeons can learn to recognise more than 100 images, and recall them more than two years later. They also have a head for numbers. A few years ago, Colombo and his colleagues showed pigeons pictures containing differing quantities of objects. The researchers trained the birds to peck first at the picture with one object, followed by the picture with two objects, and finally the picture with three objects.
Next, they showed the pigeons two new pictures, each featuring between four and nine items. Without any more training, the birds . In fact, they did just as well as rhesus macaques did on an identical task. Although this isn’t “counting” in the way we do it, Colombo says, it does show that pigeons and primates are equally good at understanding abstract numerical rules.
Video: Bird-brained pigeons perform like primates
It isn’t the only example of pigeons thinking in an abstract way – a significant step up from the conditioned learning that Skinner studied. These birds understand “transitive inference”, for example, which is a logic puzzle that Aristotle once pondered. If you know Mary is taller than John and John is taller than Anne, you can infer that Mary must be taller than Anne. Pigeons are able to apply this same line of reasoning to five individuals.
They can even recognise different styles of painting. at Keio University in Tokyo, Japan, . The birds were then able to generalise their knowledge, applying their understanding of Monet and Picasso to other impressionists and other cubists, respectively. Intriguingly, however, their visual system seems to work in a substantially different way to our own, making it difficult to imagine how they see these works (see “A bird’s eye view”).
“The pigeons applied their knowledge of Monet and Picasso to other impressionists and cubists”
Aside from our art, pigeons keep an eye on our behaviour, too – perhaps unsurprisingly, given that we live in such close proximity. This was demonstrated not in the lab, but in a city park. Two people, similar in age, stature and skin colour but with different coloured coats that covered most of their bodies, fed the pigeons. One acted neutrally toward the birds, while the other chased them.
It didn’t take long for the pigeons to learn to avoid the hostile human. They still avoided that person even after the feeders switched coats, indicating that .
Such abstract learning suggests a certain level of intelligence. But there is much more to our own minds than an ability to notice patterns. We can plan for the future, for instance – giving our behaviour greater flexibility. Anecdotal accounts would imply that pigeons are also capable of planning in advance – think of the “ that board the London Underground, wait a couple of stops, and then get off, day after day.
Although we can’t ever know for sure what’s going on in these birds’ minds, Colombo has some evidence that pigeons really can think about the future. In 2010, he trained a pair of pigeons to peck on three objects in a specific order: first a red circle, then a green clover-like shape and finally a blue dot. He then presented the same three objects to the birds, but with a twist. After they had pecked the red circle, the clover and dot suddenly switched places. If the pigeons had planned the entire pecking sequence at the start, one would expect them to take longer to peck on the correct objects while they updated their plan – and that is just what Colombo found.
In a second test, opaque white squares covered the clover and the dot immediately after the birds pecked the circle. Even without seeing the shapes they still pecked in , further suggesting they had formed a pecking-order plan from the outset.
Planning a step or two ahead may not sound too impressive. Yet the study suggests that pigeons aren’t just using a set of automatic responses. Somewhere in their brains, they appear to be thinking things through.
Along these lines, the spotlight has recently fallen on whether these birds are feathered philosophers, capable of a particularly sophisticated trait called metacognition. Also known as “thinking about thinking”, this awareness of one’s own knowledge is what allows us to judge whether we are certain of an answer on a quiz, or need to look up a word in a dictionary. It is often considered to be the apex of mental abilities by those studying animal consciousness. Although some primates and dolphins are thought to meet the grade, most animals fail.
Some enticing evidence came last year. Pigeons were trained to learn a series of three-item lists and peck symbols on a screen in a particular order. In some cases, the birds were given the option to peck on a “hint” icon for help. They were more likely to ask for help when first learning a new list than during later stages of training. This suggests they were assessing their knowledge and . A similar study showed that pigeons sought more hints as they performed more difficult tasks, again implying that they have a handle on what they do and don’t know.
Yet other studies, including a series of tests by Sara Shettleworth, a psychologist at the University of Toronto, Canada, have found mixed evidence that pigeons can think about thinking. That’s why researchers including Colombo and Watanabe remain unconvinced. In Colombo’s view, the evidence for this advanced skill is somewhat suspect even in non-human primates.
Similarly tantalising, though inconclusive, clues may hint that pigeons have another form of self-awareness: self-recognition. To explore this trait, psychologists have long used the “mirror test”, in which a researcher surreptitiously applies a spot of dye to the animal, then places it in front of a mirror. If the animal tries to rub at the dye on its own body, this suggests it is self-aware enough to grasp the idea of a reflection.
Apes, dolphins and even the magpie have passed the mirror test – but testing pigeons has been trickier. Given their grubby appearance, you may not be surprised to hear that pigeons aren’t particularly bothered by a mark on their feathers. So they first had to be trained to peck at dye spots marked onto their bodies. The researchers then marked body parts that could only be seen in a mirror. Sure enough, the pigeons used their reflection to locate the spot and peck accordingly.
For Güntürkün, however, that extra training makes it hard to draw firm conclusions. “Chimps, orang-utans, elephants and magpies were never trained in this way. They just do it spontaneously,” he says. “I don’t argue that when pigeons look in the mirror they don’t have any sort of understanding that it is them. But the way we test pigeons doesn’t prove it.”
Perhaps the decisive evidence will come from Watanabe’s lab. He has shown that a pigeon can recognise itself on video. The birds were trained to peck a keyboard when they saw themselves on live video feeds but not when they saw pre-recorded films of themselves. Then they watched more live video, but with a delay. They continued to peck, even when the video had a 2-second time lag. In other words, the , despite the time delay.
Recognising oneself on video is rare in non-human animals, Watanabe says; only apes, elephants and dolphins are known to possess that skill. What’s more, he thinks he has found evidence that pigeons can recognise themselves spontaneously in front of a mirror. That study, though, is still being reviewed for publication so he can’t yet discuss the details.
Whether or not pigeons are capable of thinking about themselves, it’s clear they are much smarter than most of us give them credit for. Does that mean we should raise them to the status of apes and elephants?
Don’t invest in a pigeon pedestal just yet. Many animals would probably be able to perform similar mental acrobatics, says Güntürkün, if we tested them systematically. “Never underestimate the cognitive power of animals,” he says.
To Colombo, the conclusion isn’t that pigeons are avian Einsteins, but that primates aren’t so special after all. As more and more animals are shown to perform mental tricks that rival our own, it all points to one question, he says: “Are humans unique?” The loathed pest of city centres may suggest not.
Parallel paths
The brains of pigeons and people look radically different – not surprising given that they have been evolving in different directions for 300 million years. Some of the basic wiring was sorted out before we went our separate ways, but many other structures have evolved in the millennia since.
Nevertheless, the brains of birds and people may not be as different as they seem (see diagram). In primate brains, the prefrontal cortex is in charge of our ability to plan behaviour to meet a goal, a skill called executive control. To do this, it filters which bits of information flowing into our brains are important, and which can be forgotten, says Mike Colombo, a neuroscientist and animal cognition researcher at the University of Otago in New Zealand.FIG-mg29670701.jpg
He has found that . In pigeons, a region called the nidopallium caudolaterale filters information to decide what needs to be remembered and what can be forgotten.
But it is not just that bird brains do something similar to ours. They also do it in the same way. “Down to the neurological level, what the cells are doing seems to be the same,” says Colombo – even though the respective regions in humans and birds are thought to have evolved separately.
In other words, there may be a limited number of ways that evolution can solve the same cognitive problems, says Onur Güntürkün, a psychologist at Ruhr University Bochum in Germany. When it comes to brain and behaviour, he says, “nature may have invented the wheel twice”.
This article appeared in print under the headline “Who you calling featherbrain?”
