[CaseyJParker]

The expected average for a straight guess with absolutely zero exposure to the material would still be slightly positive. If nothing else, there's intuition and ingenuity, which place a person just a touch above a truly random guess-generating-machine.

[hyperpape]

With four answers, you get .25 + (.75)(-.5) = -.125 for guessing.

Edit: yeah, I badly misread this.

[cercatrova]

That's what the parent is saying to be not applicable to the situation; humans are not simply true random guessing machines but are able to reason and eliminate choices, which would increase the expected value to be positive.