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Proceedings Paper

Does the thinking aloud condition affect the search for pulmonary nodules?
Author(s): Stephen Littlefair; Patrick Brennan; Warren Reed; Mark Williams; Mariusz W. Pietrzyk
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Paper Abstract

Aim: To measure the effect of thinking aloud on perceptual accuracy and visual search behavior during chest radiograph interpretation for pulmonary nodules. Background: Thinking Aloud (TA) is an empirical research method used by researchers in cognitive psychology and behavioural analysis. In this pilot study we wanted to examine whether TA had an effect on the perceptual accuracy and search patterns of subjects looking for pulmonary nodules on adult posterioranterior chest radiographs (PA CxR). Method: Seven academics within Medical Radiation Sciences at The University of Sydney participated in two reading sessions with and without TA. Their task was to localize pulmonary nodules on 30 PA CxR using mouse clicks and rank their confidence levels of nodule presence. Eye-tracking recordings were collected during both viewing sessions. Time to first fixation, duration of first fixation, number of fixations, cumulative time of fixation and total viewing time were analysed. In addition, ROC analysis was conducted on collected outcome using DBM methodology. Results: Time to first nodule fixation was significantly longer (p=0.001) and duration of first fixation was significantly shorter (p=0.043). No significant difference was observed in ROC AUC scores between control and TA conditions. Conclusion: Our results confirm that TA has little effect on perceptual ability or performance, except for prolonging the task. However, there were significant differences in visual search behavior. Future researchers in radio-diagnosis could use the think aloud condition rather than silence so as to more closely replicate the clinical scenario.

Paper Details

Date Published: 22 February 2012
PDF: 9 pages
Proc. SPIE 8318, Medical Imaging 2012: Image Perception, Observer Performance, and Technology Assessment, 83181A (22 February 2012); doi: 10.1117/12.911586
Show Author Affiliations
Stephen Littlefair, The Univ. of Sydney (Australia)
Patrick Brennan, The Univ. of Sydney (Australia)
Warren Reed, The Univ. of Sydney (Australia)
Mark Williams, The Univ. of Sydney (Australia)
Mariusz W. Pietrzyk, The Univ. of Sydney (Australia)

Published in SPIE Proceedings Vol. 8318:
Medical Imaging 2012: Image Perception, Observer Performance, and Technology Assessment
Craig K. Abbey; Claudia R. Mello-Thoms, Editor(s)

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