5 Cents Saved is less than 5 Cents Spent?

I was reading an article the other day that discussed how grocery stores are increasingly getting rid of plastic bags and offering a 5 cent refund for every reusable bag that a customer uses.  In this article, they mentioned that research has shown people are more likely to use their own bags if they are charged for a bag rather than if they get a discount off their total bill for every bag they use.

Of course, this isn’t taking into account that I can replace five plastic bags with one reusable bag.  This research is a 1 to 1 ratio.  

This doesn’t make sense to me, and yet when I think about it, I think I follow the research.  Somehow, saving 5 cents might not be worth it, but knowing that I will be charged an extra 5 cents?  No way.  I know that it doesn’t make any sense.  

So that said, I would prefer a 5 cent charge.  Ikea currently does something like this (I don’t remember the actual cost of the bag), but I will do all it takes to shove my items into my reusable bag rather than buy an extra bag.  My grocery store offers a 5 cent discount.  Of course, I use self-checkout, so there’s no one there to enter my discount, so I don’t get my money back for the bags I bring.  It doesn’t bother me, I don’t use my bags for the discount – I use them to be environmentally responsible, but probably more importantly, I use them because they’re easier to carry, since I walk to and from the grocery store.

But I’ve gotten off track.  I think it’s important to figure out why having to spend an extra 5 cents seems harder than not saving 5 cents.  It’s the same amount of money!  I wonder if people would spend and save differently if 5 cents always equaled 5 cents in their minds.