The impact of contextual information on decision-making in footwear examination: An eye-tracking study

In order to investigate whether context factors and expectations might potentially influence the decision-making of forensic footwear examiners, we collected the gaze process of experts examining the shoeprint image sets through the eye-tracking recorder. Additional to eye movement data as an objective measure, questionnaires were completed, and survey was conducted afterwards. Twenty-three qualified examiners assessed the similarity among shoe images for 22 different cases, including three sets were laterally reversed. We divided the experiment into two sessions, and then compared the examiners' performance with and without contextual information. The results showed the effects of contextual bias manipulate on both behavioral data and eye tracking data. The consensus and accuracy of examiners with contextual information were higher than those without contextual information. In the eye-tracking data, there is a significant difference between fixation counts and saccadic counts under contextual information. In addition, we found that the contextual information produced significant changes in inter-examiner consistency as measured by the Earth Mover Distance metric. However, there is no significant statistic differences in saccadic amplitude and total fixation duration of the examiners after exposure to contextual information. Our research results are instructive for understanding the cognitive process of shoeprint examination involved in real cases. In this process, stimuli related to context factors may affect decision-making and behavior. Implications for contextual effect causes are discussed.