Numerous experiments have demonstrated the possibility of attitude polarization. For instance, Lord, Ross & Lepper (1979) partitioned subjects into two groups, according to whether or not they believed the death penalty had a deterrent effect, and presented them with a set of studies on the issue. Believers and skeptics both become more convinced of their initial views; that is, the population polarized. Many scholars have concluded that attitude polarization shows that people process information in a biased manner. We argue that not only is attitude polarization consistent with an unbiased evaluation of evidence, it is to be expected in many circumstances where it arises. At the same time, some experiments do not find polarization, under the conditions in which our theory predicts the absence of polarization
