“…It follows that the possible n-grams of the scanpath ABC are A, B, C, AB, BC and ABC; whereas the possible subsequences of this scanpath include all the n-grams above plus AC; thus, omitting the central letter B. Frequency-based methods count frequencies of n-grams and compare the distributions of these in different groups [Kübler et al 2017]. A distance measure can be used to find significant differences between groups in terms of distributions of n-gram frequencies [Davies et al 2016;Kübler et al 2014Kübler et al , 2017. These techniques have been applied more or less successfully to viewing artwork, search tasks, video game play, driving tasks, and medical image interpretation [Davies et al 2016[Davies et al , 2017Kübler et al 2014Kübler et al , 2017 Hidden Markov Modelling, another frequency-based method, works by generating probability distributions for sequences of AOI transitions.…”