As rationalists, we are trained to maintain constant vigilance against common errors in our own thinking. Still, we must be especially careful of biases that are unusually common amongst our kind.
Consider the following scenario: Frodo Baggins is buying pants. Which of these is he most likely to buy:
If you're like me, your answer is (c). Frodo, as we know, is about 4' tall, so his inseam is much more likely 20'' than 30''.
But like me, you'd be wrong. Since there aren't *actually* any hobbits, all we know is that we're talking about a person named Frodo Baggins, who is male. And the most common pants size is 32/30, so the correct answer, given our actual state of knowledge about the real world, is (a).
This is what researchers call Fictional Bias, and there is evidence that it affects virtually every domain of decision-making. The mistake is using information from fictional sources in real contexts. It is the more-pernicious cousin of generalizing from fictional evidence - instead of merely generalizing, we treat real objects and persons as though they are the specific fictional entities they resemble.
We're of course familiar with particularly egregious examples of people confusing fiction with reality. For example in the 1930's, there were multiple cases where someone was killed for having the same name as the serial killer of children from the movie M. But these could be written off as merely disturbed individuals. But as it turns out, we're affected by this bias in our daily lives.
Examples abound in the literature, though the name "fictional bias" is not always used. A 1984 study by Dr. Sidney Zweibel and Dr. Emilio Lizardo asked subjects to trust someone with an unusual name. Subjects were 70% less likely to trust when the person had the same name as a fictional villain. A 1989 study by Dr. Wayne Szalinski established that subjects were 89% more likely to agree to take an experimental drug, when it was named after a fictional drug (for example Ephemerol).
The moral? It stands to reason that we need to be careful where our intuitive inferences come from. For a group that consumes so much science fiction and fantasy, we must be especially on our guard. (Also, this post was an April Fools prank; the effect may or may not be real, and all citations are either irrelevant or fictional.) It might even behoove us to discourage the reading of fiction amongst aspiring rationalists.
Kahneman, D. and Frederick, S. 2002. Representativeness revisited: Attribute substitution in intuitive judgment. Pp 49-81 in Gilovich, T., Griffin, D. and Kahneman, D., eds. Heuristics and Biases: The Psychology of Intuitive Judgment. Cambridge University Press, Cambridge.
Szalinski, W. 1989. Recollection of fictional medication. Journal of Cognitive Minification, 67: 173-186.
Tversky, A. and Kahneman, D. 1982. Judgments of and by representativeness. Pp 84-98 in Kahneman, D., Slovic, P., and Tversky, A., eds. Judgment under uncertainty: Heuristics and biases. New York: Cambridge University Press.
Tversky, A. and Kahneman, D. 1983. Extensional versus intuitive reasoning: The conjunction fallacy in probability judgment. Psychological Review, 90: 293-315.
Zweibel, S. and Lizardo, E. 1985. Fictional bias in interpersonal trust. Cross-Dimensional Neurosurgery, 45: 307-324.