Facts About Dogs' Brains

Your dog's brain is only one-tenth the size of yours, but science is finding that our canine companions are smarter than you may think. While a dog's intelligence compares in human terms to that of a 2-year-old child, dogs have skills no human of any age could ever hope to possess. Research into dogs' brains and how they work, though in its infancy, provides an amazing window into the human-canine relationship.

Researchers at Emory University wanted to see what was happening in the brain of awake, unrestrained dogs -- something that had not been done before. They trained dogs to walk into and sit in an MRI machine. The dogs were also taught using hand signals -- one signal meant they would receive a treat, and the other meant they would not. When the dogs saw the signal for a treat, the region of the brain associated with rewards in humans lit up with activity. The researchers concluded that the brain scan showed something most pet guardians would say they already knew. Dogs pay close attention to signals from humans, and these signals work closely with the brain's reward system.

A border collie named Rico convinced scientists at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, that dogs could learn human language and could start to form guesses about what new words meant. This process is called fast mapping and was thought to be a trait of humans only until the study of Rico and his 200-word vocabulary. Scientists set up experiments to test whether Rico actually understood the meaning of new words and concluded that he did.

A dog's sense of smell is 10,000 to 100,000 times greater than that of humans. Part of that is attributable to the dog's amazing nose, which has about 50 times more olfactory receptors than the human nose. Part of it is also attributable to the dog's brain. Proportionally, a dog's brain assigns 40 percent more space to analyzing smells than the human brain does. Dogs have been trained to communicate with humans to use the power of their nose and brain to help detect cancer and drugs, find lost people and warn of bombs.

The brain structures that cause emotions in dogs resemble the analogous structures in humans. Dogs also have the same brain waves as humans when they are sleeping and are thought to dream, just as we do. Research at Goldsmiths College in London showed that dogs felt empathy for not only their human guardians when they cried but also for human strangers. A study at the University of Vienna in Austria led researchers to the conclusion that dogs also understand when they are being treated unfairly.