Information repetition in evaluative judgments: Easy to monitor, hard to control

The sampling approach [Fiedler, K. (2000a). Beware of samples! A cognitive-ecological sampling approach to judgment biases. Psychological Review, 107(4), 659–676.] attributes judgment biases to the information given in a sample. Because people usually do not monitor the constraints of samples and do not control their judgments accordingly, systematic judgment biases occur. Three experiments demonstrate this for an obvious sampling constraint, the emptiness of merely repeated information. When evaluating stock market shares, participants did not correct for the repetition of positive or negative information about a share. Although original and repeated information was reliably distinguished in estimates of occurrence (successful monitoring), preferences were misled by mere repetition of success and failure reports (unsuccessful control). This effect could even override a share’s actual success rate. Explicit instructions to ignore repetitions provided no remedy; however, a cognitive load manipulation reduced repetition’s undue influence. Possible reasons for and benefits of this lack of direct metacognitive control are discussed.