Pigeons as Good as Radiologists at Spotting Breast Cancer, Scientists Say

Humans pride ourselves on our supreme intelligence: our clever inventions, and the ability to use them. But the rest of the animal kingdom is gaining on us. Plenty of animals, from octopuses to orangutans, use tools. And now, scientists say, pigeons presented with mammogram results can spot breast cancer.

This sounds completely outrageous—unless you know something about pigeons. They’ve got terrific vision and can learn to use touchscreens. They also consistently outperformed human subjects on a classic logic problem called the Monty Hall dilemma

University of Iowa psychologist Edward Wasserman has studied pigeon cognition for years. "Research over the past 50 years has shown that pigeons can distinguish identities and emotional expressions on human faces, letters of the alphabet, misshapen pharmaceutical capsules, and even paintings by Monet vs. Picasso," Wasserman said this week in a press release. "Their visual memory is equally impressive, with a proven recall of more than 1800 images."

Wasserman’s work caught the eye of Richard Levenson, a pathologist and vice chair of strategic technologies at UC Davis. Levenson wondered if the pigeons could learn to interpret medical images.

This is hardly an easy or straightforward task. Radiologists train for years to learn how to read the nuanced visual information in slides, X-rays, and MRI results. Could a group of pigeons get the basics in just a few days?

They sure could. In a paper published this week in PLOS ONE, Levenson, Wasserman, and their colleagues reported that the trained pigeons could tell the difference between cancerous and normal tissue. And the pigeons were really, really good at it. 

Image Credit: © 2015 Levenson et al

Researchers first trained the pigeons to spot abnormalities using a process called operant conditioning, in which the birds were rewarded with food only when they chose the right image between two histology slides. After only 15 days, the pigeons could easily identify which slides showed cancerous cells and which didn’t. 

To make sure the birds weren’t just memorizing the images, the researchers began using brand-new images that the pigeons had never seen before. The pigeons continued to ace the test, spotting breast cancer with 85 percent accuracy. And it only got better from there: When the researchers combined the results of four birds, the flock’s accuracy rate reached a mind-boggling 99 percent.

The pigeons also learned to scan mammogram results for evidence of cancer in little lumps of calcium called microcalcifications. Again, the pigeons nailed it. Their success rate was lower this time, only 72 percent—but that still puts them on par with human radiologists.

Does this mean we’ll soon have white-coated pigeons in our hospitals? Not exactly. Wasserman and Levenson hope to use the birds’ talent for reading medical images to develop better imaging and image-reading techniques. Pigeons won’t replace radiologists in the clinic, but they may pick up some of the grunt work. 

“While new technologies are constantly being designed to enhance image acquisition, processing, and display, these potential advances need to be validated using trained observers to monitor quality and reliability," Levenson said in the press release. "This is a difficult, time-consuming, and expensive process that requires the recruitment of clinicians as subjects for these relatively mundane tasks.

"Pigeons' sensitivity to diagnostically salient features in medical images suggest that they can provide reliable feedback on many variables at play in the production, manipulation, and viewing of these diagnostically crucial tools, and can assist researchers and engineers as they continue to innovate."

Crafty Crows Can Build Tools From Memory

Scientists have discovered yet another reason to never get on a crow's bad side. According to new research reported by Gizmodo, members of at least one crow species can build tools from memory, rather than just copying the behavior of other crows—adding to the long list of impressive skills that set these corvids apart.

For the new study, published in the journal Scientific Reports, an international team of scientists looked at New Caledonian crows, a species known for its tool usage. New Caledonian crows use sticks to pick grubs out of logs, sometimes stashing these twigs away for later. Tools are so important to their lifestyle that their beaks even evolved to hold them. But how exactly the crows know to use tools—that is, whether the behavior is just an imitation or knowledge passed down through generations—has remained unclear until now.

The researchers set up the experiment by teaching eight crows to drop pieces of paper into a box in exchange for food. The birds eventually learned that they would only be rewarded if they dispensed either large sheets of paper measuring 40-millimeters-by-60 millimeters or smaller sheets that were 15-millimeters-by-25 millimeters. After the crows had adapted and started using sheets of either size, all the paper was taken away from them and replaced with one sheet that was too big for the box.

The crows knew exactly what to do: They ripped up the sheet until it matched one of the two sizes they had used to earn their food before and inserted it into the dispenser. They were able to do this with out looking at the sheets they had used previously, which suggests they had access to a visual memory of the tools. This supports the "mental template matching" theory—a belief among some crow experts that New Caledonian crows can form a mental image of a tool just by watching another crow use it and later recreate the tool on their own, thus passing along the template to other birds including their own offspring.

This is the first time mental template matching has been observed in birds, but anyone familiar with crow intelligence shouldn't be surprised: They've also been known to read traffic lights, recognize faces, nurse grudges, and hold funerals for their dead.

[h/t Gizmodo]

Jana Mueller
Ravens Can Figure Out When Someone Is Spying on Them
Jana Mueller
Jana Mueller

Corvids, the family of birds that includes crows and ravens, are canny beasts. They've been known to exercise self-control, count, hold grudges, and more. Now, new research suggests they possess at least a rudimentary Theory of Mind—the ability to attribute mental states to others.

A study in Nature finds that ravens can tell when someone else can see them, guarding their food when a peephole to their cache is open. While previous research suggested that birds might have an awareness of other animals' mental states, the results have been inconclusive. The Nature study is evidence that corvids can do more than just track other birds' gaze; they may understand the concept of "seeing."

Vienna-based researchers set up two rooms separated by windows that could be closed with covers. These covers had peepholes in them that could also be opened or closed. First, the 10 ravens were each allowed to cache food, while other birds were in the next room and the windows were open or closed. Then, they were trained to look through the peepholes to find food in the other room, so that they knew that the holes could be used to see through the window covers. Afterwards, each of the ravens was again presented with food with one of the two peepholes open. The adjacent observation room didn't have any birds in it, but the researchers played the sounds of another raven recorded during one of the previous trials.

When the birds heard the sounds of another raven in the next room, and the peephole was open, the birds behaved as if they knew they were being watched—they hid their cache of food quickly and didn't add more food to it as often, as if they knew that it might be compromised. However, they behaved normally when the peephole was closed.

This suggests that ravens don't just track their competitors' gaze to know when they’re being watched, but can infer from past experience when they can be seen.


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