That is a question I can answer with a certainty!  Yes they can, especially
if its bad behavior.
I once had a dog who behaved pretty good until a friend brought her dog with her when she moved in with us. Her dog was a runner. When the door opened he bolted. Needles to say my dog learned that amazing trick. We had a hard time breaking him of that but we did.
They can learn from other dogs at dog parks, friends or even at a kennel while your away on vacation.
never underestimate your best friend