# The Ground Zero mosque and cognitive biases

Among the many other things involved in this controversy, stereotypes of Muslims are not exactly helping. As this blog is (excessively) fond of arguing, ethnic stereotypes are partly fueled by an obscure cognitive bias known as Reversing Conditional Probabilities. As a long ago Aid Watch post argued (sorry for indulging in self-quotation, but hey it's August, time for reruns):

{People perceive} from media coverage that the probability that IF you are a terrorist, THEN you are a Muslim is high. Unfortunately...{we are confusing} this with the relevant probability, which is the chance that IF you are a Muslim, THEN you are a terrorist (which is extremely low even if the first probability really is high, because terrorists are very rare).

This blog is so obsessed with **Reversing Conditional Probabilities (RCP)** that we have also linked it to exaggerating the effect of Affirmative Action on women's careers and why Dani Rodrik likes industrial policy.

Of course, there could be the same cognitive bias about Christians from the Muslim side (which will no doubt be exacerbated by the Ground Zero mosque controversy). The probability that IF you are an anti-Muslim bigot, THEN you are Christian could be reasonably high. But since explicit bigotry is still pretty rare, the correct probability -- IF Christian, THEN anti-Muslim bigot -- is far lower.

Most of our readers don't seem to share our enthusiasm for RCP, the most boring, wonkiest topic of all time. But the obstinate educator never gives up hope that teaching probability theory could promote world peace.