What the Dog Knows by Cat Warren Page A

function, was the only thing that helped the beasts escape. The conclusion held sway in the research community for over a century. “Based on Thorndike’s experiments and others like them, scientists now believe that dogs have rather limited powers of reasoning, certainly inferior to those of chimpanzees (and even a few birds),” John Bradshaw wrote in 2011.
    And so it goes, even as dogs’ noses become more and more popular with the public. For instance, one group of studies showed that dogs ranked from “okay” to “fine” at distinguishing between fraternal and even identical twins’ scent on gauze pads. When dogs were asked to choose the scent difference between identical twins living in the same house and eating the same food, however, they failed miserably. That study’s conclusions were clear about the outer limits of dogs’ scenting capacity.
    These are exactly the kinds of studies that irritate cognitive psychologist William “Deak” Helton, at the University of Canterbury, New Zealand, an expert in the science of working dogs. Experiments like the twin-distinguishing studies, he said, are akin to putting undergraduate students on a flight simulator, studying their performance, and coming to conclusions about the capabilities of trained pilots. One doesn’t need to go all the way to the vastly experienced Captain Chesley “Sully” Sullenberger safely landing a US Airways jet on the Hudson River to think Deak might have a point.
    â€œMore studies need to be done on highly skilled dogs,” Deak said. “The problem, of course, is these dogs are already likely to be working and are too valuable.” It’s not that the research done with untrained dogs is invalid, he noted; it’s that those dogs haven’t had their noses—or their cognitive abilities—trained and developed.
    The twin-distinction story ends well. A group of scientists and ethologists in Czechoslovakia, where much of the groundbreaking work on dog cognition has taken place, decided to do another study on the identical-twin scent-discrimination problem. These researchers used trained scent-detection dogs. Their 2011 study showed that well-trained German shepherds could easily and correctly distinguish between the scent profiles of identical twins, even those who lived in the same environment and ate the same food.
    Properly trained and handled, dogs will find almost anything we ask them to. For many substances, they can find small amounts. A 2006 study (albeit with a tiny sample) showed that trained dogs could detect one to two parts per trillion of n-Amyl acetate, a banana-scented solvent. That’s the equivalent of a drop of water in twenty Olympicsized swimming pools.
    It’s not universally true that dogs can smell at much lower concentrations than humans do. Larry Myers, who has been doing research on sniffer dogs since 1982, thinks it’s silly to try to quantify which dogs have the best noses, which species have the best noses, or even to compare human noses with dog noses. Yet he couldn’t help doing a coupleof quick, informal experiments comparing his lab workers’ noses with dogs’ noses on odors. Myers tested one group of workers and dogs on acetone, a cleaning solvent common around labs. “My lab workers could smell it at lower concentrations than the dogs could.” But with eugonal, a carnation-ey, clove-y compound that Myers started using as a standard pretest compound before having dogs perform more elaborate tests, they showed a response at one millionth of the concentration that lab workers could.
    The old dogs’ tales don’t end at levels of concentration. There’s also the strict correlation between the number of dogs’ smell receptor cells and their scenting ability. At first, as I read the nose literature, I ranked a German shepherd’s nose below a bloodhound’s but well above most other