While we tend to be optimistic about our abilities, we are pessimistic about our luck:
We analyze the answers of a sample of 1,540 individuals to the following question "Imagine that a coin will be flipped 10 times. Each time, if heads, you win 10C. How many times do you think that you will win?" The average answer is surprisingly about 3.9 which is below the average 5, and we interpret this as a pessimistic bias. We find that women are more "pessimistic" than men, as are old people relative to young.
Added: Benja Fallenstein notes "if there is no [personal] gain associated to the coin tossing, the average [guess] is 4.9, and 90% answer 5.
I wonder if the subjects are being rational, in the sense that they're avoiding the ludic fallacy:http://www.fooledbyrandomne...
Within the rules of the games, yes, they'll win 5, but this exact game they've never played, and more importantly never played with the experimenter, who they cannot 100% trust. So the subjects are just rationally injecting real-world experience or street-smarts into their assessment. I recall an example from when I was 6 years old. I bet a marble with this kid, and I won. Was the game over? Well in a sense, no. The kid cried to teacher, who forced me to give him the marble back. Similarly, if the experimenters don't value the keeping of one's word then they could give the subjects $0 regardless.
P.S. (On OB what's the procedure when you have a new idea about an old post. Is it worth commenting on?)
Jay, Carl, Weldon [the "good luck attributed to skill, therefore people think they have bad luck" faction]: I think I'd buy your explanation if it turned out that the majority of the subjects really try to come up with an estimate based on experience (if somebody came up with a clever way to test for it), but the way I'm imagining the situation, it seems much more likely to me that most subjects confabulate an answer that feels right. Maybe it's because I don't have enough experience with games of luck to form an opinion based on that, and therefore imagine average people don't either? -- On the other hand, I like to play Tali (a Yahtzee-clone) on the computer, trying to beat my own highscores (of all the silly ways to waste time, this must occupy a special place), and I pay attention to the order of types in Tetris, and in both cases I actually get the feeling (not being taken seriously, don't worry) of being lucky above chance; and still I can see myself answering <5 in the study more easily than answering >5.
Dagon's (and Wagster's) position hits closer to my intuitions, for what that's worth...