The Effects of Incomplete Information on the Formation of Attitudes Toward Behavioral Alternatives

The effects of incomplete information on the evaluation of behavioral alternatives were investigated for two different decision topics: evaluation of banks and of political candidates. Forty-three subjects were presented descriptions of banks or candidates varying on three informational dimensions differing in subjective importance to the subject. The descriptions varied in accord with a 4 × 4 × 4 factorial design, with each factor corresponding to one of the informational dimensions. The levels of each factor indicated that the behavioral alternative was above average, average, or below average on the informational dimension, or that there was no information available on the dimension. Five general psychological processes describing how individuals might react to the missing information were identified and tested. Results were generally consistent with a hybrid model of average imputation and partial devaluation. Reactions to missing information tended to be consistent across decision topics. Implications of the results for attitude formation and decision models of choice are discussed.