Keywords

usability, digital biomarkers, mental workload, user experience, eye-tracking, mouse tracking

Abstract

Usability, the extent to which a product can be used with satisfaction and efficiency, is critical for its success, yet traditional assessment methods are often subjective or resource-intensive. This dissertation adapts the concept of digital biomarkers—objective, quantifiable data typically used to inform health outcomes—to summative usability assessment. By examining passively collected mouse and eye movement data, this research pinpoints reliable digital biomarkers that forecast subjective usability ratings, effectively assessing the 'health' of digital systems. Three studies were conducted to demonstrate that metrics based on eye and mouse-cursor movements can accurately predict standard usability survey scores across a wide array of circumstances and tasks. The first study established that distinct cognitive processes involved in visual search, such as object recognition and search guidance, differentially predict subjective usability ratings. The second experiment confirmed that mouse movement metrics, including total distance traveled and average speed, are significant predictors of mental workload and post-task satisfaction across different websites. The third experiment directly compared the predictive power of both biomarker types in naturalistic settings, revealing that oculomotor metrics, particularly fixation count, served as the most robust and universal predictor of mental workload and subjective usability scores. The findings demonstrate that while both eye and mouse movements are effective biomarkers, their predictive utility is assessment-specific; for instance, total mouse distance best predicted immediate task satisfaction, whereas fixation count was optimal for post-test system evaluations. Ultimately, this work provides a methodology to advance usability benchmarking, enabling scalable and objective assessments of the user experience through passive behavioral data.

Completion Date

2025

Semester

Fall

Committee Chair

Joseph Schmidt, Ph.D.

Degree

Doctor of Philosophy (Ph.D.)

College

College of Sciences

Department

Psychology

Format

PDF

Identifier

DP0029759

Document Type

Thesis

Campus Location

Orlando (Main) Campus

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