Think back to your school days. Remember learning about that Pavlov guy? Well, a German dog food brand, GranataPet is trying out Pavlov’s experiment in reverse…on humans!

GranataPet launched an interactive billboard campaign conditioning dog owners to check in at a billboard on Foursquare. Once checked in, the billboard dispensed a sample of the dog food for pooches to enjoy. The dog gets a treat while the owner sees how much the dog is enjoying the new food.

The result? The campaign generated hundreds of new customers for GranataPet dog food and increased the brand’s viral presence because of Facebook users posting their Foursquare check ins to their Facebook profile. Did I mention this was all done on small budget?