An EEG study of Detection without Localisation in Change Blindness

Abstract

Previous studies of change blindness have suggested a distinction between detection and localisation of changes in a visual scene. Using a simple paradigm with an array of coloured squares, the present study aimed to further investigate differences in event-related potentials (ERPs) between trials in which participants could detect the presence of a colour change but not identify the location of the change (sense trials), versus those where participants could both detect and localise the change (localise trials). Individual differences in performance were controlled for by adjusting the difficulty of the task in real time. Behaviourally, reaction times for sense, blind, and false alarm trials were distinguishable when comparing across levels of participant certainty. In the EEG data, we found no significant differences in the visual awareness negativity ERP, contrary to previous findings. In the N2pc range, both awareness conditions (localise and sense) were significantly different to trials with no change detection (blind trials), suggesting that this ERP is not dependent on explicit awareness. Within the late parietal positivity range, all conditions were significantly different. These results suggest that changes can be 'sensed' without knowledge of the location of the changing object, and that participant certainty scores can provide valuable information about the perception of changes in change blindness.

Physiological Correlates of Sensory Consciousness: Evidence for a Perceptual Awareness Negativity

“…Upon review, however, these experiments suffer from a few critical problems, the most common being a failure to account for the spatial lateralization of VAN topography. Five used target stimuli that were lateralized to one hemifield, but the authors failed to consider the lateralization of the VAN during data analysis by processing signals from both hemispheres (Babiloni et al, 2006;Lamy et al, 2008;Salti et al, 2012;Boncompte & Cosmelli, 2018;Scrivener et al, 2019). Subsequent studies closely following the procedures of Lamy et al (2008) and Salti et al (2012) while controlling for lateralization in their analyses did observe a VAN (Koivisto & Grassini, 2016;Eklund & Wiens, 2018).…”