If mice are so smart, can they know their numbers are declining by being trapped? Such as bro and sis gone?

Why would they keep following the paths of other members of their family. I am still trying to figure out how many mice we have! Never had a problem with mice. This last month we realized we had to set traps, no more catching and releasing (humane) as I first did. I do feel bad about it, don't laugh too hard, those of you who HATE mice. I actually somehow respect the little creatures, and their intelligence. I just can't LIVE with them and their droppings everywhere, and hearing them run through the rafters!! Does anyone know if it's true that they do not feel pain? A woman answered someones question regarding this, and the woman apparently worked in a lab and had been around these creatures for 20 years, and she claims they have no "pain centers". I can't hardly believe this. They are after all a warm blooded lil thing. Is this true? Unfortunately, me and my husband will have to start trapping the lil things again this evening! Please don't respond with a yes or no answer. And I do realize one mouse dead means a hundred less mice. I just hate killing the little b-terds. Thanks for any and all advice on how to do it other than slap traps, and glue traps, and catch and release traps, and cats. Believe me, my cats are good mousers, but tapeworm pills are expensive too! Do sonic repellers really work to rid them? Thanks to all other intelligent humans, ha. Really, thanks for any time you spend on what may seem like silly questions.