Document Type

Dissertation

Date of Award

2026

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

First Advisor

Michael Granaas

Abstract

Dashboard displays in command center environments benefit from design guidelines informed by perceptual and cognitive research. This dissertation examines how spatial hierarchy and chartjunk affect knowledge retention from dashboard displays, using a mixed-methods approach that combines formative qualitative studies with controlled experiments. Three formative studies, an expert review, a heuristic analysis with three reviewers, and semi-structured interviews with IT professionals identified spatial hierarchy and chartjunk removal as the design guidelines most likely to affect dashboard comprehension. A subsequent co-creation study with IT professionals refined these findings and informed experimental stimulus development. Two experiments tested these guidelines using a dashboard knowledge retention paradigm. In two experiments hierarchy showed a larger effect than chartjunk. Critically, spatial hierarchies that did not align with the knowledge being tested (room and floorplan conditions) produced worse recall than no hierarchy at all. These findings suggest a general principle: visual structure aids comprehension when it reinforces task-relevant understanding but imposes cognitive costs when it competes with or distracts from that understanding. This finding reframes Tufte's chartjunk critique as being less about ink volume per se and more about whether visual elements align with the cognitive work the visualization is meant to support.

Subject Categories

Psychology

Keywords

chartjunk, command centers, dashboards, human factors, knowledge retention, spatial hierarchy

Number of Pages

109

Publisher

University of South Dakota

Included in

Psychology Commons

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