The results of one study indicate that dogs pick up on our hormonal levels in interaction with them.

The results of one study indicate that dogs pick up on our hormonal levels in interaction with them. Looking at owners and dogs participating in agility trials, the researchers found a correlation between two hormones: the men’s testosterone levels, and the dogs’ cortisol levels. Cortisol is a stress hormone—useful for mobilizing your response to, say, flee from that ravenous lion—but also produced in conditions that are more psychologically than mortally urgent. Increases in the level of the hormone testosterone accompany many potent elements of behavior: sex drive, aggression, dominance displays. The higher the men’s pre-agility-competition hormonal levels, the higher the increase in the level of stress in the dogs (if the team lost). In a sense, the dogs somehow knew that their owner’s hormonal level was high, by observing behavior or through scent or both—and they “caught” the emotion themselves. In another study, dogs’ cortisol levels revealed that they were even sensitive to the style of play of human playmates. Those dogs playing with people who used commands during play—telling the dog to sit, lie down, or listen—wound up with higher post-play cortisol levels; those playing with people who played more freely and with enthusiasm had lower cortisol at play’s end. Dogs know and are infected by, our intent, even in play.

Being known and predicted by our dogs is no small part of our fondness for them. If you have experienced an infant’s first smile at you as you approach, you know the thrill of being recognized. Dogs are anthropologists because they study and learn about us. They observe a meaningful part of our interaction with each other—our attention, our focus, our gaze; the result is not that they can read our minds but that they recognize us and anticipate us. It makes the infant human; it makes the dog vaguely human, too.

Noble Mind

It’s dawn and I try to sneak out of the room without waking Pump. I can’t see her eyes, so dark they’re camouflaged against her black fur. Her head rests peacefully between her legs. At the door, I think I’ve made it—tiptoed and breath-held to avoid her radar. But then I see it: the swell of her lifted eyebrows tracking my path. She’s on to me.

The dog, as we’ve seen, is a master looker, a skilled user of attention. Is there a thinking, plotting, reflective mind behind that look? The development of the human infant’s looking into using attention marks the blossoming of the mature human mind. What does the dog’s looking tell us about the dog’s mind? Do they think about other dogs, about themselves, about you? And the timeworn but still unanswered question of dog minds: Are they smart?


Dog owners, like new parents, always seem to have a handful of stories at the ready describing how smart their charges are. Dogs, it is claimed, know when their owners are going out, and when they are coming home; they know how to hoodwink us and they know how to beguile us. News reports buzz with the latest discovery of the intelligence of dogs: of their ability to use words, count or call 911 in an emergency.

To verify this anecdotal impression, some have designed so-called intelligence tests for dogs. We’re all familiar with intelligence tests for humans: pen-and-paper creations that require you to solve SAT-like problems of word choice, spatial relationships, and reasoning. There are questions that test your memory, your vocabulary, your declining math skills, and your simple pattern-finding ability and attention to detail. Even putting aside whether the result is a fair assessment of intelligence, the design does not translate obviously to testing dogs. So revisions are made. Instead of tests of advanced vocabulary, there are tests of simple command recognition. Instead of repeating a list of digits read aloud, a dog may be asked to remember where a treat was hidden. Willingness to learn a new trick may replace the ability to figure complex sums. Questions loosely mimic experimental psychology paradigms: of object permanence (if a cup is placed over a treat, is it still there?), learning (does your dog realize what foolish trick you desire him to do?), and problem-solving (how can he get his mouth on that food you’ve got?).

Formal studies of groups of dogs on these kinds of abilities—mostly cognition about physical objects and the environment—yield what at first seem to be unsurprising results. By bringing dogs to a field baited with treats and timing dogs’ speed in finding them, researchers have confirmed that dogs use landmarks to navigate and find shortcuts. This behavior is consistent with what their wolflike ancestors would probably have done in finding food and finding their way. Dogs are, of course, pretty good at all tasks that involve getting themselves to food. Given a choice of two piles of food, dogs have no trouble choosing the larger one—especially as the contrast between them grows. Turn a cup over a bit of food and dogs go right for it, knocking the cup and revealing the treat. Dog subjects have even learned how to use a simple tool—pulling a string—to get an attached biscuit that was otherwise out of reach.

But dogs don’t pass all the tests. They typically make lots of mistakes when presented with piles of three versus four biscuits, or of five and seven: they choose the smaller amounts just as often as the larger. And they develop preferences for piles on the left or the right, which leads them to make even more blatant errors. Similarly, their skill at finding hidden food gets worse as the hiding gets more complicated. And their tool use also starts to look less impressive as the trials get trickier. When there are two strings, and only the more distant one is attached to an alluring biscuit, dogs nonetheless go for the nearer string, the one attached to nothing. They don’t seem to understand the string as a tool: as a means to an end. Indeed, they may have succeeded in the original case simply by pawing and mouthing at the problem until accidentally solving it.

A dog owner tallying her dog’s score in these dog intelligence tests might find that he’s scoring closer to Dim but happy than Top of the obedience class. Is that it, then? Is he not smart after all?