Can Dogs Learn by Observation?

I'm very interested in the question of dogs learning by observation. The 'decisive' paper that proved that dogs don't learn by observation was a very limited study, I believe, involving two dogs with no particular reinforcement history, in which the observer dog failed to learn some task... And somehow it went into the zeitgeist as a firm conclusion, one I was totally prepared to believe in myself, at one time. I thought that dolphins do learn by observation, and dogs don't. Then I started giving seminars, and seeing all kinds of observational learning going on.