Measuring the Effect of Think Aloud Protocols on Workload using fNIRS

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Measuring the Effect of Think Aloud Protocols on Workload using fNIRS

Matthew Pike, Horia A. Maior, Martin Porcheron, Sarah Sharples, Max L. Wilson

CHI 2014 | 2014 | View on Publisher's Website

Abstract

The Think Aloud Protocol (TAP) is a widely used verbalization technique in HCI research to gain insights into user experiences, but little work has explored the cognitive impact of TAPs on study participants. This paper employs functional near-infrared spectroscopy (fNIRS) to observe how different types of TAPs affect cognitive workload. Participants performed mathematical tasks under four conditions: nonsense verbalizations, passive think-aloud, invasive think-aloud, and silence. The study measured task performance, subjective workload (NASA-TLX), and brain activity via fNIRS. Results show that invasive TAPs impose greater cognitive demand than passive ones, while nonsense verbalizations lead to significantly higher workload. These findings contribute to refining TAP methodologies and highlight the potential of fNIRS for real-world HCI studies.