Comparative Judgment Processes: The Effects of Task Objectives and Time Delay on Product Evaluations
研究发现消费者比较产品时会忽略共同特征，导致评价偏差；任务目标（比较或单独描述）和时间延迟会影响这种偏差，并波及后续对其他产品的评价。
Consumers who compare products may often ignore features that the choice alternatives have in common. As a result, they often evaluate products more favorably when the products have unique positive features but common negative features than when they have unique negative features but common positive ones. Two studies examined contingencies in the occurrence of these "cancellation" effects and explored their implications for people's evaluations of not only the products being compared but other products they encounter subsequently. Some participants were explicitly told to compare two products at the time they received information about them. They not only disregarded the products' common features when initially evaluating these products, but disregarded evaluatively similar features of a third product they encountered some time later. Other participants were initially told to describe each product separately. In this condition, they formed an overall impression of each product individually, and so cancellation effects were not apparent. Nevertheless, their preference for one product over the other was based on a comparison of the products' individual features that they could recall at the time of judgment rather than on the global impressions they had formed when the product information was first presented.