The payment for most of the tasks on Mechanical Turk and other things like it is just not worth the time for almost any task I've seen. Which is really sad, because it'd be awesome if it were worth it.
It's interesting to read all the comments that say "$1?!?! You're ripping off these people! Why would anyone ever do anything on Mechanical Turk?" How many hours do y'all spend on Hacker News? How long did it take you to write those comments? How much were you paid for it?
In strictly economic terms, Turkers are getting ripped off a lot less than news.YCers are. After all, $1 is infinitely more than $0. We labor for free so that Paul Graham can have a viable online community and pick of the top posters for his seed capital firm.
Of course you may be being philosophical about it. In which case, no we have no real way of knowing if they even think.
I'm pretty sure that might be above the US minimum wage.
While that may be true for you, there are plenty of places across the globe where $1 (with a chance of $50) is not an insignificant amount.