Yes, if the trick isn’t too, well, tricky, says Elizabeth Niven, a dog trainer and behaviorist at the Dogwood Farm Kennel, in Troy, Missouri. Case in point: A few years ago, Niven took in a 12-year-old English pointer who had never set foot in a house and therefore had no concept of house training. “Six weeks later, he was totally housebroken and completely well behaved,” she says. But if you’re expecting an old dog (or human) to pick up a complicated skill that requires quick reflexes or mental agility, you might face some frustration. That’s because as a brain ages, it loses cells, which, in turn, lose some of their “branches” that reach out and connect with other cells. These physical changes slow reaction time and the speed of message transmission. “Learning a new skill, like playing the piano or speaking a foreign language, would be harder at age 80 than age eight, since all bodily processes decline as we age,” says Linda M. Espinosa, an associate professor of learning, teaching, and curriculum at the University of Missouri, in Columbia. “But it’s certainly not impossible.”