His Favorite Toy

We buy these inexpensive toys at Walmart, practically in bulk (3 or 4 at a time). That way, when Guapo chews one up, we have a backup to keep him occupied. Usually, I pick the toys, and Guapo loves them. On the rare occasion that R picks one, though, that one always ends up being Guapo's FAVORITE. So, of these two toys:

Can you guess which one I picked and which R picked? Here's Guapo proving my point. I have him "sit" and "wait" as I place both of them equal distances from him. Then I give him the "good boy" command (which means it's okay for him to get up and get the toy).
And which does he go for? That's right, the blue one, the one R picked out. The one that was chewed up 10 seconds after he got it! On the other hand, the green one (the one I picked) has survived and thrived for nearly a month.

Now to explain to R why he is responsible for picking up all the little pieces of blue plastic scattered all over the house...