The electrophysiological effect of working memory load on involuntary attention in an auditory–visual distraction paradigm: an ERP study

Event-related brain potentials (ERPs) were used to examine the electrophysiological effect of working memory (WM) load on involuntary attention caused by a task-irrelevant sound in an auditory–visual distraction paradigm. The different WM loads were manipulated by requiring subjects to remember the order of either three digits (low-load condition) or seven digits (high-load condition), and the irrelevant auditory stimuli consisted of repetitive standard sounds (80%) and environmental novel sounds (20%). We found that the difference waves (novel-minus-standard) showed significant MMN and Novelty-P3 components in the two WM load conditions. The amplitude of MMN increased with increasing the WM load, which indicated a more engaged change detection process under high-load condition. Then, the amplitude of Novelty-P3 was attenuated under high-load condition, which indicated a much reduced involuntary orienting of attention to novel sounds when increasing the WM load. These results indicated the top–down control of involuntary attention might be mainly active at the early change detection stage and the control of the later involuntary orienting of attention might be passive.