Developing Dynamic Audio Navigation UIs to Pinpoint Elements in Tactile Graphics

Neural mechanisms of face perception are predominantly studied in well-controlled experimental settings that involve random stimulus sequences andfixed eye positions. Although powerful, the employed paradigms are far fromwhat constitutes natural vision. Here, we demonstrate the feasibility of ecolog-ically more valid experimental paradigms using natural viewing behaviour, bycombining a free viewing paradigm on natural scenes, free of photographerbias, with advanced data processing techniques that correct for overlap effectsand co-varying non-linear dependencies of multiple eye movement parame-ters. We validate this approach by replicating classic N170 effects in neuralresponses, triggered by fixation onsets (fixation event-related potentials[fERPs]). Importantly, besides finding a strong correlation between both exper-iments, our more natural stimulus paradigm yielded smaller variabilitybetween subjects than the classic setup. Moving beyond classic temporal andspatial effect locations, our experiment furthermore revealed previouslyunknown signatures of face processing: This includes category-specific modu-lation of the event-related potential (ERP)’s amplitude even before fixationonset, as well as adaptation effects across subsequent fixations depending ontheir history.