Free rides and observational advantages occur in visualizations when they reveal facts that must be inferred from an alternative representation. Understanding whether these concepts correspond to cognitive advantages is important: do they facilitate information extraction, saving the ‘deductive cost’ of making inferences? This paper presents the first evaluations of free rides and observational advantages in visualizations of sets compared to text. We found that, for Euler and linear diagrams, free rides and observational advantages yielded significant improvements in task performance. For Venn diagrams, whilst their observational advantages yielded significant performance benefits over text, this was not universally true for free rides. The consequences are two-fold: more research is needed to establish when free rides are beneficial, and the results suggest that observational advantages better explain the cognitive advantages of diagrams over text. A take-away message is that visualizations with observational advantages are likely to be cognitively advantageous over competing representations.

当搭便车和观察优势揭示了必须从其他表示形式推论得出的事实时，就会在可视化中出现。了解这些概念是否与认知优势相对应很重要：它们是否有助于信息提取，节省推理的“推论成本”？本文介绍了在与文本相比的可视化场景中对搭便车和观察优势的首次评估。我们发现，对于欧拉图和线性图，搭便车和观察优势带来了任务性能的显着提高。对于维恩图，尽管它们的观察优势比文本产生了显着的性能优势，但对于搭便车并非普遍如此。结果有两方面：需要更多的研究来确定搭便车何时有益，结果表明，观察优势更好地解释了图胜于文本的认知优势。一个重要的信息是，具有观察优势的可视化可能比竞争性表示在认知上更具优势。