Varieties of Confirmation Bias

Abstract

This chapter reviews research concerning a variety of confirmation biases and discusses what they have in common and where they differ. The overall picture is one of heterogeneous, complex, and inconsistent phenomena, from which it is nevertheless possible to discern a general direction, namely a general tendency for people to believe too much in their favored hypothesis. The chapter discusses ideas about how to reconcile the apparent heterogeneity and the apparent generality of confirmation biases. There has been considerable interest among cognitive and social psychologists in the idea that people tend to hang on to their favored hypotheses with unwarranted tenacity and confidence. This tendency has been referred to as perseverance of beliefs, hypothesis preservation, and confirmation bias. Research in this area presents a rather heterogeneous collection of findings: a set of confirmation biases, rather than one unified confirmation bias. There are often substantial task-to-task differences in the observed phenomena, their consequences, and the underlying cognitive processes. There is no consensus about such basic questions as what is a favored hypothesis, against what norm is a belief unwarranted, and under what circumstances are people susceptible or not susceptible to a bias.