Can you figure out what a person is like by how their dog reacts?

Generally you would be able to determine what behavior the dog observed in its' person as it grew up, so to say 'yes...almost' seems about right.

More like by how [b]my[/b] dog reacts.

Maybe i knew a dog owner once who admitted to kicking the dog really badly when it was a pup to make it submissive . He said that's how police train their dogs. He now has a dog collar on it, its older now and the collar gives the dog shocks. the dog looks nervous and sad. I think the guy is a big sad bully and control freak for doing that.

Not by their dogs reaction, I trust my own dogs when it comes to people. Mastiff breeds are a pretty good at reading people. Though I have mutts as well who are nearly as capable.

Ha I hope not.