Research suggests smarter people tend to live longer. But because they also tend to smoke, drink, and eat too much, experimental results to prove this have come out skewed (they're just horrible test subjects). Now, scientists in the United Kingdom believe they’ve found a simple way around this problem: Get more reliable test subjects — dogs.

Researchers from the London School of Economics and Edinburgh University devised a study involving a unique IQ test for dogs, which would then be used to test for a relationship between intelligence and longevity. Dogs are ideal for this type of research for a few reasons. First, their minds work similarly to ours, especially when it comes to problem-solving abilities. Second, they don’t smoke, drink alcohol, use drugs, or eat more than what they’re given. The researchers say this makes them a perfect control group. And third, because they’re not subjected to income or educational disparities, there’s less room for bias than there would be in a human study.

“In addition, dogs are one of the few animals that reproduce many of the key features of dementia,” co-author Dr. Rosalind Arden said in a press release. “So understanding their cognitive abilities could be valuable in helping us to understand the causes of this disorder in humans and possibly test treatments for it.”

For the study, the team of researchers had 68 border collies — one of the world’s most intelligent dogs — perform a series of cognitive tasks to test for intelligence. These included finding a reward behind a barrier and choosing a plate that had the most food, The Independent reported. Like humans, the dogs that excelled at one cognitive task tended to excel at all of them, and before the team knew it they had weeded out the brightest of the bunch.

As mentioned, several studies have found links between intelligence and a person’s lifespan. A 2001 study, for example, found that the higher people scored on an IQ test at age 11, the more likely they were to live to at least 76. Some experts say this jump in longevity is due to these people's ability to better handle stress, which gives them resilience. Another study found about 95 percent of the intelligence-longevity relationship could be explained by genetics.

In truth, we have no conclusive evidence to explain why smarter people live longer. Man’s best friend has been dependable all this time; maybe we can depend on it once more.

Source: Arden R, Adams MJ. A general intelligence factor in dogs. Intelligence . 2016