This happens when a proven method of doing something that brings a desired response (i.e. stealing underwear always elicits a chase from a human), all of a sudden stops working. The extinction burst is the part where the dog tries the proven method again and again, and hundred times stronger before they figure out that it just doesn't work anymore. Human equivalent: you're at the elevator. You pressed the button 10 seconds ago. This has always made the elevator come and pick you up. For some reason, there's no sign that the elevator's coming. You press it again. And again, and again and again, harder and harder, with more force (extinction burst!), until finally you just give up and use the stairs. If the original method doesn't work anymore, why use it?!