Biology Reference
In-Depth Information
mestic dogs and cats in them, and waited for them to figure out how to escape. The per-
formance of both species was disappointing. Thorndike's conclusion was that operant con-
ditioning, rather than any independent cognitive 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 distinguish-
ing 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 under-
graduate students on a flight simulator, studying their performance, and coming to conclu-
sions 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.
“More 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 Czechoslov-
akia, 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-scen-
ted 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
