Expert decision-making in evolving situations

The extent to which cognitive biases are found in realistic expert decision problems is examined empirically. Army intelligence analysts were given a realistic battlefield scenario and asked to make preliminary decisions about the most likely enemy avenue of approach and to give their confidence level. Subsequently they were asked to reconsider their decisions in the light of updated intelligence reports, containing some items which confirmed and some which contradicted their early decisions. Three such updating judgments were requested. Finally they were asked to rate each information item in terms of the degree to which it supported or contradicted their hypotheses. Regardless of the initial hypothesis, confidence was generally high and tended to increase as the situation evolved. Confirming evidence was sought, and was weighted significantly higher than disconfirming information. Contradictory evidence was usually recognized as disconfirming, but was weighted lower than supportive evidence, often being regarded as neutral and sometimes as deliberately deceptive. These and other findings suggest that expert judgments in this type of situation should be treated with caution and might be improved through the use of graphic aids, training, and probes to explore conditions under which alternative inferences would be likely