Effects of task structure and confirmation bias in alternative hypotheses evaluation.

We empirically examined the effectiveness of how the Analysis of Competing Hypotheses (ACH) technique structures task information to help reduce confirmation bias (Study 1) and the portrayal of intelligence analysts as suffering from such bias (Study 2). Study 1 (N = 161) showed that individuals presented with hypotheses in rows and evidence items in columns were significantly less likely to demonstrate confirmation bias, whereas those presented with the ACH-style matrix (with hypotheses in columns and evidence items in rows) or a paragraph of text (listing the evidence for each hypothesis) were not less likely to demonstrate bias. The ACH-style matrix also did not confer any benefits regarding increasing sensitivity to evidence credibility. Study 2 showed that the majority of 62 Dutch military analysts did not suffer from confirmation bias and were sensitive to evidence credibility. Finally, neither judgmental coherence nor cognitive reflection differentiated between better or worse performers in the hypotheses evaluation tasks.