When do populations polarize? An explanation

Numerous experiments demonstrate attitude polarization. For instance, Lord, Ross & Lepper presented subjects with the same mixed evidence on the deterrent effect of the death penalty. Both believers and skeptics of its deterrent effect became more convinced of their views; that is, the population polarized. However, not all experiments find this attitude polarization. We propose a theory of rational updating that accounts for both the positive and negative experimental findings. This is in contrast to existing theories, which predict either too much or too little polarization.