Real world $1k vs. $1M probably wouldn't be as 50/50 as the experimental results suggest.  I bet most of the people choosing two-boxing are thinking of it like a logic puzzle rather than a real life choice.

Bell_curve

I think at $1k and $1M I'd also one-box it, but this would be motivated by vague superstitious notions / ambiguity aversion and also trying to minimize the feeling of regret.  (If I 1-box, at most I lose out on $1,000 but if I 2-box I could feel like I missed out on $1M)