Cognitive Affordances in Visualization: Related Constructs, Design Factors, and Framework

TL;DR

The paper addresses how visualization communicates information through cognitive affordances, bridging affordance theory from psychology and HCI with visualization practice. It develops a formal framework consisting of design decisions, reader characteristics, and a hierarchy of afforded information to predict and evaluate conveyed messages. It surveys related constructs and experimental methods, and demonstrates practical guidance for evaluation and redesign, including a PRO-line-chart example and a framework-driven workflow. The work highlights unintentional affordances, discusses the relationship between precision and cognitive affordance, and outlines future validation efforts and infrastructure for cataloging cognitive affordances.

Abstract

Classically, affordance research investigates how the shape of objects communicates actions to potential users. Cognitive affordances, a subset of this research, characterize how the design of objects influences cognitive actions, such as information processing. Within visualization, cognitive affordances inform how graphs' design decisions communicate information to their readers. Although several related concepts exist in visualization, a formal translation of affordance theory to visualization is still lacking. In this paper, we review and translate affordance theory to visualization by formalizing how cognitive affordances operate within a visualization context. We also review common methods and terms, and compare related constructs to cognitive affordances in visualization. Based on a synthesis of research from psychology, human computer interaction, and visualization, we propose a framework of cognitive affordances in visualization that enumerates design decisions and reader characteristics that influence a visualization's hierarchy of communicated information. Finally, we demonstrate how this framework can guide the evaluation and redesign of visualizations.

Figures (15)

• Figure 1: These two charts encode identical data, but the bar chart affords discrete categories, whereas the line chart communicates a single continuous variablezacks-tversky-bars-linesshah-graph-comprehension-1999.
• Figure 2: Our framework of cognitive affordances in visualization consists of three high-level components: design decisions, readers, and a hierarchy of afforded information. The impacts of design decisions are moderated by reader characteristics, which dictate the likelihood that different information is communicated.
• Figure 3: Examples of visual encoding manipulations. In (a) bars are grouped by position on the left, and color on the right. In (b) data is visualized with bar height and then point and line placement.
• Figure 4: Examples of visual arrangement manipulations. (a) shows pie charts that are identical but slightly rotated. (b), shows pie charts with differently arranged slices.
• Figure 5: Examples of contextualizing visual elements: (a) title wording changes, (b) annotation shapes changes.