This study addresses the issue of preference for natural versus synthetic products in different contexts, specifically food, medicines, and cosmetics. Participants were 52 students aged 14-15 years from two schools. We analysed the choices and justifications offered by 28 students from one of the schools before and after receiving an instructional module (nine 60-minute lessons over three weeks) focused on decision-making about natural and processed foods. The goal of instruction was not to guide them towards a particular preference (natural or processed foods) but rather to enable them to make well-reasoned and more scientifically-informed decisions. Transfer of learning to the contexts of medicines and cosmetics was also examined. The responses of students in this experimental group were compared with those of 24 comparison students from the other school who did not receive the instruction. Results suggested that the teaching received by the comparison group (based solely on the standard science curriculum in Spain) does not encourage students to abandon assumptions regarding the inherent superiority of natural products, or to justify their preferences in ways that may be considered on-target with respect to the secondary-level science curriculum. By contrast, a shift towards more scientifically informed choices and reasoning was observed following participation in the instructional module. However, there was limited evidence of transfer of learning from the food context to the other two contexts considered. Only in the medicines context did the experimental group show minor improvements at post-test, suggesting that students perceive greater similarity between food and medicines than between food and cosmetics.

这项研究解决了不同环境下对天然产品与合成产品的偏好问题，特别是食品、药品和化妆品。参与者是来自两所学校的 52 名 14-15 岁学生。我们分析了其中一所学校的 28 名学生在接受专注于天然食品和加工食品决策的教学模块（三周内九节 60 分钟课程）前后提供的选择和理由。指导的目的不是引导他们选择特定的偏好（天然或加工食品），而是使他们能够做出合理且更科学的决定。还审查了将学习转移到药品和化妆品领域的情况。该实验组学生的反应与来自另一所学校的 24 名未接受指导的学生的反应进行了比较。结果表明，对照组接受的教学（仅基于西班牙的标准科学课程）并不鼓励学生放弃有关天然产品固有优越性的假设，或以可能被认为是目标的方式证明他们的偏好是合理的关于中学科学课程。相比之下，在参与教学模块后，观察到了向更科学的选择和推理的转变。然而，有限的证据表明学习从食物背景转移到所考虑的其他两种背景。只有在药品方面，实验组在测试后才表现出微小的进步，这表明学生认为食品和药品之间的相似性比食品和化妆品之间的相似性更大。