Abstract
Road crossing contexts necessitate the spread of visual attention across varying locations of the visual field, which may have dire consequences if performed inadequately. Analyses of eye-movement patterns suggest differences in strategies employed by pedestrians of different developmental ages, where adults and older children tend to overtly monitor for the appearance of new cars while covertly monitoring existing cars as they move through their visual field. This pattern contrasts with younger children, who tend to follow moving cars with their eyes, neglecting to monitor for the appearance of new cars. The ability of adults to monitor cars with their covert visual attention is, however, mostly inferred by their performance in road-crossing tasks rather than specific evidence of divided visual attention. To determine whether there is an objective index of this division of visual attention in a road-crossing context, we combined a smooth pursuit eye-movement paradigm with a frequency-tagging EEG technique, whereby visual attention was measured through synchronised neural responses to the periodic flicker (30 Hz) of an overtly attended moving stimulus. To induce a division of visual attention, half of the blocks involved only one car moving across the screen, while the other half involved the possibility of a second car appearing during the trial. Event-related spectral perturbation analyses of the 30 Hz oscillations at the occipital lobe showed a clear decrease in synchrony at specific times in the trial when visual attention was divided by the need to monitor for the appearance of new stimuli, relative to when attention was undivided. The co-registration of EEG with eye-movements in a smooth-pursuit paradigm revealed a unique neural signature of divided attention during a simulated road-crossing context. This neural marker could thus be used in all populations as an index of effective information sampling for road crossing.
Meeting abstract presented at VSS 2018