To get it right, the dogs had to resist the impulse to try to take the shortest
path to reach the treat — which would only cause them to whack into the
barrier and bump their heads against the plastic — and instead walk
around the
barrier to one of the open sides.
Whenever your objective is so close yet you look all
around and are unable to figure out a way to scale the mountainsides or find a
path through a
barrier, it can be quite irritating.