[mcpie]

It's not so much social training as it is the exposure time (which you also mentioned). Exposure time was so long that it was nearly impossible to smile in pictures. See for example the picture of the photographer himself at the stream - the running water in the river is a blur. I'm surprised the exposure time isn't that high in these pictures though. The shot of the workmen in the woodshop is distinctly modern by showing 'action'.