Me too! We are living in a 100+ year old house, but so far no one has been acting weird but it's something I've watched for.
Mind you back when we lived in Ontario and I'd have Bayley out on the trails for walks, sometimes she'd start acting weird, running back and forth, sniffing the air. Not ghosts I'm sure but there was something out there that I couldn't see, smell or hear. She'd snff, run back and forth and then in front of me a ways and stop and give me that 'hey c'mon let's go!! look. This from a dog who loves her runs and bogging. I tended to listen to her!! It only happened when we were out on the trails and never at the dog park we used to go to