Abstract To assess whether smiley stamps work as a motivational incentive to promote fruit and vegetable eating among children, we conducted a field experiment in ten primary schools in five European countries using one control and one treatment school per country. The six-week experiment was split into three two-week phases before, during and after the smiley was implemented. During the smiley phase, the children received a smiley stamp for choosing a portion of fruits or vegetables. We find an increase attributed to the smiley stamp on children’s fruit and vegetable choice and consumption, but also waste. Comparing the effects across countries, we observe significant variations in the smiley effect. This study thus demonstrates, in general, that a low-cost, easy-to-implement incentive such as a smiley stamp has the potential to motivate school children to increase their fruit and vegetable consumption; the study simultaneously underscores the high relevance of context for the effects of incentives.

中文翻译：

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笑脸作为动机对儿童水果和蔬菜选择、消费和浪费的影响：在五个欧洲国家的学校进行的实地实验

摘要 为了评估笑脸图章是否可以作为促进儿童食用水果和蔬菜的动机，我们在五个欧洲国家的十所小学进行了一项实地实验，每个国家一所对照学校和一所治疗学校。为期六周的实验分为三个为期两周的阶段，在实施笑脸之前、期间和之后。在笑脸阶段，孩子们会因选择一部分水果或蔬菜而收到笑脸图章。我们发现增加归因于儿童水果和蔬菜选择和消费上的笑脸印记，但也造成浪费。比较不同国家的效果，我们观察到笑脸效果的显着差异。因此，这项研究表明，总体而言，低成本、易于实施的激励措施，例如笑脸图章，有可能激励学童增加水果和蔬菜的消费量；该研究同时强调了背景对激励措施效果的高度相关性。