Evaluating gaze control on a multi-target sequencing task: The distribution of fixations is evidence of exploration optimisation

• Published in: Computers in biology and medicine Vol. 42; no. 2; pp. 235 - 244
• Main Authors: Veneri, Giacomo, Rosini, Francesca, Federighi, Pamela, Federico, Antonio, Rufa, Alessandra
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.02.2012; Elsevier Limited
• Subjects: Adult; Attention; Computational Biology; Eye Movements - physiology; Eye tracking; Female; Fixation, Ocular - physiology; Fixations; Humans; Internal Medicine; Male; Middle Aged; Other; Psychomotor Performance - physiology; ROC Curve; Saccades; Trail Making Test; Trial Making Test; Vision Tests; Saccades; Fixations; Eye tracking; Trial Making Test; Attention
• ISSN: 0010-4825; 1879-0534
• DOI: 10.1016/j.compbiomed.2011.11.013

Abstract Many high cognitive applications, such as vision processing and representation and understanding of images, often need to analyse in detail how an ongoing visual search was performed in a representative subset of the image, which may be arranged into sequences of loci, called regions of interest (ROIs). We used the Trial Making Test (TMT) in which subjects are asked to fixate a sequence of letters and numbers in a logical alphanumeric order. The main characteristic of TMT is to force the subject to perform a default and well-known path. The comparison of the expected scan-path with the observed scan-path provides a valuable method to investigate how a task force the subject to maintain a top-down internal representation of execution and how bottom-up influences the performance. We developed a mechanism that analyses the scan path using different algorithms, and we compared it with other methods: we found that fixations outside the ROI are direct influence of exploration strategy. The paper discusses the method in healthy subjects.