Asymmetric Shape Variability Biases Proportion Judgments With Icon Arrays.

Area of Science:

• Cognitive Psychology
• Information Visualization
• Risk Communication

Background:

• Icon arrays are widely used for communicating risk and uncertainty to the public.
• Prior research indicates icon arrays can improve probability perception compared to other formats.
• Little is known about how icon array design, specifically perceptual characteristics and spatial arrangement, influences risk perception.

Purpose of the Study:

• To investigate how icon shape variability and spatial arrangement in icon arrays affect proportion judgment and risk perception.
• To build on visual perception research suggesting shape variation impacts perceived numerosity.

Main Methods:

• Three experiments were conducted using a proportion judgment task.
• Icon arrays varied in spatial arrangement (grouped vs. random configurations).
• Icon arrays also varied in shape variability within target and non-target categories.

Main Results:

• Proportion judgments were highly accurate for grouped icon arrays, irrespective of shape variability.
• For random arrangements, irrelevant shape variability in one category biased proportion judgments.
• Biased judgments increased perceived quantity for the category with shape-varied elements.

Conclusions:

• Perceptual variations in icon shape, though irrelevant to the task, can significantly alter quantity perception in icon arrays.
• Findings provide crucial insights for designing icon arrays to improve accurate risk communication.
• Grouped configurations are recommended for reliable risk perception, while random configurations require careful design to avoid perceptual biases.