Suppose you were given two options, and told that whatever money results would be given to an EA charity. Would you find it difficult to choose a 1% shot at $1000 over a sure $5? What if you were told that there are a thousand people being given the same choice? What if you're not told how the gamble turns out? What if all the gambles are put in a pool, and you're told only how many worked out, not whether yours did?