Psychology DOES apply to the real world

I recently had the opportunity to spend some time with my parents, and not coincidentally much of the time I was also reading my textbook. I found many of the examples provided in the textbook to be interesting, and I wanted to see how they would hold up while conducting my own experiment. I ended up quizzing my dad on "Popular Psychology Knowledge." To my surprise, he answered True to only two of the questions, though all are actually false. I dismissed this result as an anomaly at first, but upon further reading, I realized my dad was simply reacting to demand characteristics, meaning he was altering his experimental behavior based on what he thought the experimenter (me) wanted to hear.

This principle sparked my interest, and I researched a little more into it. I found this article detailing the phenomenon. This source of bias is an obvious way that researchers can be forced into incorrect conclusions, and thus is noteworthy as a pitfall for experimental design. Can any of you think of a way to completely eliminate the effect of demand characteristics?

<-Martin Orne, pioneer of demand characteristics research.