Try hot dogs with garlic salt sprinkled on and nuked for a few seconds. Tiny tiny little pieces. And if food doesn't work, how about toy motivation? At 16 weeks, your pup should already be learning commands and in a puppy class. I would look into clicker training... that may help? Check out kikopup on youtube. She has some AWESOME videos. Or just type in clicker training in youtube. It really has done wonders for the amount Delta has learned.