Collect them all! Increasing product category cross-selling using the incompleteness effect
研究发现，当消费者看到不完整的产品类别集合（如未完成的菜单或拼图）时，会因追求完整而更可能从多个类别中交叉购买，从而提升交叉销售。
Abstract The familiar state of tension associated with an incomplete collection or an unfinished jigsaw puzzle is predicted by Lewin’s (1926; 1935) field theory. This feeling evokes a drive to completion—a phenomenon we label the incompleteness effect —which is useful to marketers endeavoring to cross-sell products and services. In three studies using online product configurators, we find that consumers faced with visual representations of incomplete product category collections, such as an evening drinks menu or a puzzle with its pieces representing services, are significantly more likely to complete the collection or finish the puzzle by cross-purchasing from a greater number of product or service categories as compared to those using a conventional online shopping format. We identify theoretical mechanisms through which the incompleteness effect works and potential moderators for the effect. Findings suggest that managers offering products or services across several categories can increase cross-selling by eliciting people’s drive toward completion.