The eyes are the window to the soul, and as anyone who's looked deep into the eyes of a beloved pooch can attest, dogs are no exception. There's an intensity in a dog's gaze that seems to speak of vast depths of wisdom and understanding. Skeptics might claim that dog lovers are reading too much into their dog's' behavior, but scientific research on canine intelligence is stacking up in the dogs' favor. Here are five examples to put those sourpusses (no offense, cat people) in their place:
1 - Dogs respond to words, not just tone of voice
A dog might perk up when you say "Who's a good boy?" and "Who wants a treat?" — but does the dog know what 'good boy' and 'treat' mean, or is it just excited because you're excited? Evidence suggests that they're picking up on more than just your tone of voice. One study used fMRIs, which track activity in the brain, to show that dogs process language and nonverbal sound in two different hemispheres of the brain - just like humans. The brain scans showed more response in the left hemisphere when the dogs heard familiar commands, and more response in the right hemisphere when they heard distorted speech, or commands in a foreign language.
2 - They can (probably) learn hundreds of words
Meet Chaser, the smartest dog in the world. This border collie knows over a thousand different words, can pick out each of her toys by name, and responds to commands with differences as subtle as touching something with her paw versus touching it with her nose. To be fair, Chaser is a special case - her owner has spent more than three years training her for four to five hours a day - but her abilities aren't necessarily unique. Studies like those done on Chaser show that dogs are capable of understanding language much more complex than "sit" and "stay." Chaser may not be interpreting Shakespeare anytime soon, but she's still got a bigger vocabulary than the average three-year-old human.
3 - They can read our body language
There's more to communication than just words. Body language plays an important part in conveying how we feel, and it turns out that dogs are especially adept at interpreting our physical cues. In a series of experiments, researchers put two cups on the ground, and then pointed to one that had a treat hidden underneath. The dogs were far more likely to go for the cup with the treat, even when boths cups were scented. Chimpanzees and human infants who took the same test got the right cup only half the time. In another study, dogs watched their owners open two boxes, and react positively to the contents of one and negatively to the contents of the other. Without knowing what was in the boxes, the dogs were more than eight times as likely to go to the box they thought their owner liked.
4 - They can feel jealousy
Sometimes researchers must do difficult things in the name of science, like not petting a dog, or not giving a dog a treat even when it deserves one. But it's these difficult things that help us learn more about the way dogs think, including the discovery that they can feel jealous. For example, when scientists gave a command to two dogs and arbitrarily rewarded only one of them, the second dog would eventually refuse to participate. (In humans, we refer to this as 'sulking.') In a different experiment, owners were instructed to ignore their dog in favor of either a pop-up book, or a fake robot dog. The dogs (the real ones) exhibited jealous behavior like growling, snapping, and rubbing up against their owner much more with the fake dog than with the book.
5 - They really do love you
You probably don't need a fancy study to tell you that dogs have an excellent sense of smell, or that they can recognize their owner's scent when compared to a stranger's. But something special happens when a dog gets a whiff of their owner (specifically a rag soaked in their owner's scent): the caudate nucleus, one of the structures in the brain associated with emotional attachment, lights up with activity. Of course, you already know that your dog loves you the most, but isn't it nice to have scientific proof that the feeling is mutual?