It is so cool to hear what those silent film stars sounded like. I never would have guessed that Buster Keaton sounded like that. I figured he had a classier, New England style accent.

And it is great to hear from people who have analyzed and studied this form of comedy so closely, to hear what they know innately because they've done it for so long.

Does anyone know who the other 2 comedians are? The CBC site doesn't list them.

The man on the left is Bert Lahr, who played the Cowardly Lion in The Wizard of Oz. Not sure who the other guy is.

Regarding pies in the face, when Keaton says people want to see "dignity upset" it's true. I would relate it to the second rule of comedy, that of a feeling of superiority. By seeing someone get a pie in the face, you have the feeling of relief knowing that you didn't get hit in the face with the pie. Or it can come from the feeling that the person deserved it somehow. In both instances, you have a feeling of superiority. However, that feeling can be stifled when the person being hit is respected (and therefore superior to the viewer), as Berle did to Sullivan. Then the joke backfires.

Eddie Foy Jr. is the third guy, according to a post on You Tube.