A good friend confessed to me the other day that she finds the “Frito-esque” aroma of the insides of her miniature poodle’s ears delectable. I immediately thought of Albert Camus’s semi-autobiographical novel The First Man, in which Camus describes his deaf uncle’s love affair with a “mongrel setter” named Brilliant. “They spoke in onomatopeia and relished each other’s smells,” wrote Camus of dog and man. “One must never tell [uncle] that his seldom-washed dog gave off a strong odor, especially after it had rained. ‘Him,’ he would say, ‘no smell,’ and he would lovingly sniff the inside of the dog’s big quivering ears.”

Now, as a dog owner, I wouldn’t necessarily say that I relish my dogs’ smells—particularly after they’ve perfumed themselves with the residue of badger droppings or the carcass of a small mammal. Yet I’m also not entirely offended by their otherwise unmasked scents and it would not be a stretch to say that I occasionally steal the same type of olfactory pleasures as Camus’s uncle. For whatever reason, I do not find Gulliver’s halitosis, a vaguely metallic odor mingled with meat, particularly nauseating. Nor does Uma’s chronic flatulence much disturb my nose. Were these odors emitted by another person, I would hasten to exit the room.

You may be surprised to learn just how attuned people are to their canine’s odors. In a 2000 study published in the journal Perception, Queen’s University of Belfast psychologists Deborah Wells and Peter Hepper investigated people’s ability to discriminate between their own dog’s smells and those of a stranger’s dog. In this study, twenty-six dog owners were given a blanket to place in their dog’s bed for a period of three consecutive nights. (One rule was that the dogs couldn’t be bathed for at least a month before the study began.) The owners then returned to the laboratory with this blanket, were blindfolded, and asked to take a deep whiff of two comparison blankets. One blanket was from their own dog’s bed and the other was from the bed of a foreign dog matched for age, sex, and (wherever possible) breed. Remarkably, 88.5% (23 of the 26 participants) correctly identified their own dog’s odor—a finding that the authors attribute to familiarization. However, somewhat surprisingly, the study failed to show that owners preferred this particular smell over the other one.

One possible reason for this null finding on the preference dimension may be that the study did not control for quality of attachment between the owner and his or her dog. For example, some evolutionary psychologists have posited that domesticated dogs, with their strong dependency on their owners and their rather neotenous features, hijack our parental mental modules and serve as surrogate children. If so, it may be that childless dog owners may be more motivated than others to imprint their dog’s odors on their brains, even taking a certain aesthetic pleasure in the animal’s peculiar stink. Such an unconscious mechanism would serve as a sort of attachment moderator, telling us how much we should ‘invest’ in this ‘child.’ Consider that University of Toronto psychologist Alison Fleming and her colleagues reported in 1993 in the journal Developmental Psychobiology that new mothers find the body odors of their own infants (including those smells the rest of us perceive as offal) as more attractive than non-mothers—or at least, less stomach-turning. For those of us who are not as genetically prosperous, the stench of our much-beloved pooch may be the next best thing. And as Camus wrote, “only one who neither knew nor loved dogs would see that as ridiculous.”


A final note. In 2002, Wells and Hepper replicated their olfactory discrimination study with cat owners and published these findings in the journal Perception. Participants performed at chance levels, failing to identify their own cat’s odor from that of a stranger’s cat. The authors attribute this difference between the two species to cats’ better self-grooming habits.

In this new column presented by Scientific American Mind magazine, research psychologist Jesse Bering of Queen's University Belfast ponders some of the more obscure aspects of everyday human behavior. Ever wonder why yawning is contagious, why we point with our index fingers instead of our thumbs or whether being breastfed as an infant influences your sexual preferences as an adult? Get a closer look at the latest data as “Bering in Mind” tackles these and other quirky questions about human nature.