A remarkable new study from scientists at Oregon State University has found out why dogs seem so much friendlier to their human companions than their wolf cousins. And the answer may lie in their genes, showing the incredible power of evolution and natural selection in man’s best friend.

Dogs broke off form wolves tens of thousands of years ago, and it appears that over that period of time their genes gradually changed so they became more friendly with humans. Scientists at the university studied domestic dogs and compared them to grey wolves to come to their conclusions.

After tests for both problem solving and sociability were given to the dogs and wolves, scientists were fascinated to find that despite the fact that wolves were just as good at solving problems as their domestic cousins, dogs easily outscore them in sociability. Dogs would be more likely to greet a human stranger or stare at them, where as the wolves were generally more aloof and tended to avoid humans.

“The genetic basis for the behavioral divergence between dogs and wolves has been poorly understood, especially with regard to dogs’ success in human environments,” Monique Udell, an animal scientist at Oregon State University and lead co-author of the study, said in a statement. “It was once thought that during domestication dogs had evolved an advanced form of social cognition that wolves lacked. This new evidence would suggest that dogs instead have a genetic condition that can lead to an exaggerated motivation to seek social contact compared to wolves.”