Belated "Strange, Unexplainable Gestures".

Uploaded for the Vintage Photos Theme Park theme of: PICK YOUR OWN (post a photo depicting your favorite theme from the past year)
Not necessarily a favorite - or theme, (sorry!) but I chose this photograph as a perfect illustration of the typical scenario I wrote about several weeks ago.
Months ago, I saw this in my collection and it prompted me to suggest the theme of STRANGE, UNEXPLAINABLE GESTURES.
Of course, by the time that theme came around, I had completely forgotten about this one - and searched frustratingly for something that would illustrate STRANGE, etc.
I ended up using the one below - - but reluctantly because I KNEW I had been inspired by a better one!


However, thanks to Alan's last theme of the year - I get to choose the one above, which I finally found.
So...what is going on in this photograph? The girl looks incredibly sad, the little boy joyful (but is he also trying to cup his hand?) and the strange, worried looking boy with his hands in a begging position is just baffling.
Any ideas or impressions?
This is a studio photograph with no identifying information. I would guess it was taken c. late teens, early 1920s.