3.30 Perception/decoding: Visual tasks and channels/mappings

  • Insights (Healy 2018, Ch. 1.4)
    • Getting worse: comparison on a common scale → length-based comparisons → angles → areas (latter even worse than pie charts)
    • Acute angles tends to be underestimated, and the size of obtuse angles overestimated
    • Area-based comparisons of quantities are easily misinterpreted or exaggerated (e.g., from length to squares for surface of shape)
    • Problems increase in three-dimensional spaces


Healy, Kieran. 2018. Data Visualization: A Practical Introduction. Princeton University Press.