Anybody who's ever moved a muscle toward a leash will agree that dogs understand human body language. The animals' capacity to do this, suggests new research, was evolutionarily engrained since they became people's canine companion about 15,000 years ago.
Previous studies have shown that dogs can use human cues to find hidden food. For example, dogs that watch experimenters look or point at a sealed bowl enclosing a meal then choose correctly between that container and an empty one. "Conventional wisdom would say that [people] train dogs to do this," explains Michael Tomasello, a comparative psychologist at the Max Planck Institute in Leipzig, Germany. But his team's findings support another view.