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An Empirical Study of the Effects of Gestalt Principles on Diagram Understandability

Introduction​

This paper investigates the impact of Gestalt principles—specifically proximity, similarity, and continuity—on the comprehension of software architecture diagrams. By applying these principles to modify diagrams and testing their effects on user accuracy and response time, the study aims to determine if design principles from cognitive psychology can enhance diagrammatic understanding in software engineering.

Target​

The research is relevant to software engineers, UX designers, and educators who use or design complex visual diagrams, such as UML (Unified Modeling Language) diagrams, and seek to improve clarity and ease of comprehension.

Key Insights​

  • Gestalt Principles Enhance Comprehension:
    • Continuity: Reduces response time by facilitating smooth visual flow, allowing users to follow paths or connections intuitively.
    • Proximity and Similarity: Grouping related elements enhances clarity, making it easier for users to process clustered information.
  • Complex Diagrams Benefit Most: The study found that Gestalt principles significantly improve comprehension in complex diagrams, suggesting that applying these principles may be most effective in intricate or dense visualizations.
  • Key Diagram Attributes Impacting Comprehension:
    • Line Bends and Crossings: More line bends and crossings correlate with slower response times, likely due to increased cognitive load.
    • Box Grouping and Line Length: Well-grouped boxes and shorter lines improve users' ability to trace connections, further aiding comprehension.

Supporting Data​

  • Statistical Analysis:
    • For complex diagrams, applying Gestalt principles reduced response time significantly, supporting the hypothesis that principles like continuity and proximity improve diagram readability.
    • Analysis revealed that diagrams with fewer bends and line crossings had faster average response times, emphasizing the importance of clear, uninterrupted visual flow.
  • Accuracy and Complexity: While accuracy remained high across all diagrams, response times were consistently lower in diagrams designed according to Gestalt principles, especially in complex scenarios.

Other Insights​

  • Diagram Attributes Affecting Response Time: Variables such as the number of bends, length of connecting lines, and overall layout simplicity were key factors in reducing cognitive load.
  • Learning Effects: Sequential exposure to simpler diagrams led to faster comprehension in complex diagrams, indicating a potential learning effect in users exposed to incremental diagram complexity.

Practical Applications​

  • Design with Gestalt Principles for Clarity: Apply principles like proximity and continuity in software diagrams to improve readability, particularly in complex systems.
  • Minimize Visual Interference: Limit line bends and crossings in diagrams to reduce cognitive load and speed up comprehension, especially in architecture and flow diagrams.
  • Progressive Complexity: Introduce users to simpler diagrams before presenting complex ones to leverage learning effects and improve overall diagram comprehension.

Reference​

Lemon, K., Allen, E. B., Carver, J. C., & Bradshaw, G. L. 2007. An Empirical Study of the Effects of Gestalt Principles on Diagram Understandability. Proceedings of the First International Symposium on Empirical Software Engineering and Measurement (ESEM).