The New England Journal of Medicine contains an essay about a cat named Oscar that seems to have the ability to predict when patients at a nursing home are going to die.
Are cats compassionate? Sure they are. My parents' cat definitely senses when things aren't right in their household. He snuggles next to my mom when she isn't at her best. There's a bond that develops between a pet and its caregiver that's difficult to explain, but it's (obviously) an unspoken communication that takes place and develops over time.
Granted, Oscar wanders the halls of this nursing home, but he must be able to detect something - perhaps the compassion of the nurses who raised him. I heard one of the commentators on MSNBC say that it's a little creepy, but if you've ever had a pet that you've developed a bond with, you wouldn't think it's creepy. I can remember when my grandmother was a nursing home resident and my kids would drag the farm cats in to visit all the residents. Everyone loved it! The cats were well behaved and lavished the attention from someone other than a five-year-old who would carry it everywhere. The residents enjoyed the time spent with the animals.
Cats make you work for their attention - but once you have it - it's quite an attachment.