Adjacency beats static and dynamic color in bar chart comparison.

Bar charts are among the most popular graph formats when communicating quantitative information. Recent work by Boger and Franconeri (2024, Journal of Experimental Psychology: General, 153, 1699-1704) revealed that the spatial design of simple bar charts can strongly alter which relationships viewers detect or miss. In Experiment 1, we replicated their adjacency advantage, showing that misleading relationships in grouped bar charts are more often detected when in adjacent versus non-adjacent ("interleaved") bars. In Experiment 2, we tested whether color-either static or dynamic-could benefit the detection of interleaved relationships, analogous to the advantage of adjacency in Experiment 1. The two bars containing the misleading relationship were either red or gradually changed from gray to red, with the other two bars in gray. We found no evidence for improved detection with static or dynamic color cues relative to when all bars were uniformly gray. Our findings suggest that the spatial layout of graphs strongly determines which relationships are detected, and reveals limitations of color-based highlighting in guiding our interpretation of bar charts.