Consistency and Variability Among Latent Print Examiners as Revealed by Eye Tracking Methodologies

We recorded the eye positions of 18 expert latent print examiners and 18 novice participants across two separate experiments that were designed to represent abbreviated latent print examinations. In the first experiment, participants completed self-paced latent and inked comparisons presented on a computer monitor while their eyes were tracked with a commercial eye tracker. The similarity of eye fixation patterns was computed for each group of subjects. We found greater variability under some conditions among the experts than the novices in terms of the locations visited. However, experts spent approximately 50% longer than novices inspecting the images, which may have led to differences in strategies adopted by the two groups. A second experiment used trials that always lasted 20 seconds and found that under these time-controlled circumstances, experts were more consistent as a group than novices. Experts also had higher accuracy, spent a greater proportion of time inspecting the latent prints, and had shorter saccades than novices. However, the two groups spent an equal time looking at regions that contained minutiae. The results are generally consistent with experts relying on a common set of features that they choose to move their gaze to under time-limited conditions.