I have said, elsewhere, that I do not believe the claim that humans demand a challenge in life. It has never happened but I suspect I could play solitaire and easily win every game for a very long time and not get tired of easy wins. But what about my other game? The site I play Sudoku on has 4 levels: Easy, Medium, Hard, and Evil and I cycle through them all. If I fail at a level 3 times in a row I start over at Easy. If I don't demand challenge, why do I play the Evil level? After thinking on it, I've decided that I enjoy *attainable* challenge. You can always solve a Sudoku--if you're smart enough. You can reason your way through it. Solitaire is too complex for me to reason my way through. Even if you could remember the order of the cards in the deck, it changes each time you play one. I mean, it doesn't completely reorder, but you have to memorize the deck all over again. And ideally you should be able to know what will happen to the deck if you play 2 or 3 cards in a row from it--or play a card, play a couple cards further on, etc--so you can manipulate what cards will come up next. It isn't uncommon that I play 3 cards because it is possible but the next time through the deck, that makes it so it is impossible to get a card I need, where it would've come up if I'd only played 2 cards. On top of that, chance plays a large role. You can play the best, most perfect game of solitaire and still lose because a card you need is buried. I have played games where there are no cards to play. You deal out the cards and you can't move any of them, you go through the deck and there are no cards that you can play from the deck. You lost before you even tried.
So I would modify the thesis (at least for me): Humans demand challenge in life--as long as success is possible. If the difficulty is because of random chance, the challenge isn't rewarding--to a degree. This post brought to you by fairly quickly losing 3 consecutive games of MS Solitaire--even though I played very well.
