Rats are clever animals. That is a fact. This means that they have a good capability to learn & memorise tasks by a process called association. But just like how human babies learn to talk or walk, rats need to be taught what you want them to do too. They don't speak our language, but instead they can memorise things by a process called reinforcement. They get a treat & a lot of paising if they did what you wanted them to do. 

I have been training Miyuki & Fuyume to come into their little blue box when I tap the roof & chatter to them. Then they get a small piece of rat chocolate when they get it right. First time, I make the appropriate sound & put the rats in the box, and give them treat. Miyuki memorised it in 2 goes. I tap, she comes hopping. Fuyume took about 6 practices of me pushing her bum and guiding her towards the box  to learn this. But eventually she did it. She was very very pleased, as she finally understood the idea. The problem is, when I make a tapping noise on anything, Fuyume now rushes into the box, sitting & waiting for her treat to come... *Sigh*  But she is so sweet. She traies so hard. It will be along way for her to get it right, but for now she gets a lot of hugs & kisses & encouragement.