when did YOU start smiling for pictures?

me: did most people in the 50s look that stern?
all the boys look like they're about to grease your ass
Tim: here's my question: at what point did people start smiling for portraits? I mean, in the history of photography?
what prompted people to start smiling?
look at a portrait from early 20th century... no smiling there...
me: i'd say when pictures like this started getting developed...http://bikehugger.com/images/blog/sv_victorian2.jpg
Tim: wow
say is that a belgian gazelle?
the bike, i mean
me: HAR!
Tim is typing… pics n' things!