I'm no vet / animal behaviorist either, but one of the theories I've read about is that animals are more likely to move during a "moving" barometer than they are when it is constant. In other words, they are feeding / moving as storms are approaching and then again after they leave. But they will move less during the storm and during the "nice" weather later on.
My own experiences back this up to some extent. Nearly every buck (as well as several of the does) I've shot have been either just before or just after some sort of weather system. In one year, I shot a doe during bow season as the black clouds were just starting to roll in for a big thunderstorm ; I shot a buck during rifle season first thing in the morning after it had snowed the night before ; then I shot another doe during muzzleloader season as the first big snow flakes were starting to fall from an incoming snow storm. This was just 1 year ... there have been several other instances like this as well.
So yes, I believe in it, but I don't necessarily plan my hunting around the barometer / weather systems. I hunt as much as I can either way!!
... Crayfish