If you're afflicted with cynophobia, a pathological fear of dogs, chances are that, at one time or another, some well-meaning person has advised you to remain calm and "don't let him see you're afraid." Of course, that's easier said than done, when your heart is racing and cold sweat is trickling down the back of your neck due to the fact that you're standing within lunging range of a Rottweiler … or a Yorkshire terrier.
Nevertheless, that advice does raise some interesting questions: When dogs look at a trembling, panicky human, what do they see? Do they sense your terror, and if so, does it influence their behavior toward you? Does your fear of dogs make dogs more or less likely to bite you?
Questions like these likely have perplexed humans since the first wolves started hanging around the fire hoping for scraps of our ancestors' roasted mammoth dinner. But since mammoth times, compared to many other species, dogs have done pretty well for themselves in terms of adapting to human society and coexisting with us. They fill an endless variety of roles, including animal herder, hunter's assistant, burglar alarm, guide for the visually impaired, loyal companion and playmate for children.
According to psychologist Stanley Coren, author of the book "How Dogs Think," canines' versatility and ability to interact with humans has convinced some people -- for example, the ancient Greek philosophers Plato and Diogenes -- that dogs have almost humanlike minds and moral sensibilities. Not everyone is convinced of such powers, however. For example, 17th-century French mathematician, philosopher and scientist Descartes dismissed dogs as soulless biological automatons, incapable of thinking, who respond to environmental stimuli by reflex.
In recent years, however, scientific research has shown that while dogs aren't quite the noble sages the ancient Greeks perceived them to be, they're closer in intelligence and perception skills to humans and other primates than previously thought. According to Coren, a dog can comprehend human speech and can have a vocabulary of more than 150 words, is able to solve complex problems, and even is capable of willfully tricking another dog. Moreover, evidence shows that canines study humans for cues and have some ability to interpret nuances like facial expressions. Researchers at Japan's Azabu University, for example, have been able to train canine subjects to differentiate between a smile and a blank expression in photographs of human faces. If a dog can identify a smile, it's not that much of a stretch to assume that it can pick up on the clenched teeth and wide eyes of a frightened person, not to mention changes in posture and gait.
But some canine experts think that even if you manage to keep a placid face and remain still while you're terrified, a dog will still be able to detect your fear. That's because humans, like other animals, experience physiological changes, like changes in breathing rate and perspiration, as a result of the flight-or-fight response. In particular, we involuntarily give off chemicals called pheromones when we're alarmed. Because a dog's sense of smell is thousands of times more sensitive than ours, most likely a dog can detect those chemicals, says Alexandra Horowitz, author of "Inside of a Dog: What Dogs See, Smell and Know."
But if you're worried about a nearby canine sinking its teeth into you, what you're really wondering is this: If a dog senses you're afraid, is it more likely to attack you? There doesn't seem to be much evidence that a dog's perception of a person's fear is a significant trigger for an attack. What really matters is whether the dog is afraid of you or is anxious in general.
A 2007 study of incidents in which children were bitten by dogs, published in the journal Injury Prevention, found that dogs most often bit children when they perceived a threat to their territory, food or other resources, such as toys. In addition, children who were noisy and made unpredictable movements were at greater risk of being bitten. When the aggressive animals were examined, about half of them had medical conditions, such as skin or bone disorders, which tend to cause anxiety in dogs -- and thus, make them more likely to feel the urge to protect themselves.