A parallel literature has examined the N400 automaticity issue by combining a priming paradigm with visual masking of either the prime or the target. Visual pattern masking results when a visual pattern is flashed at the same spatial location before or after a brief display of the item of interest and has the consequence of reducing that item’s conscious perceptibility (i.e., reportability). Overall, masking of primes has been found to attenuate but not to eliminate N400 effects, although Holcomb and colleagues convincingly attribute the residual to occasional prime visibility under masking (Holcomb & Grainger, 2009). A similar account, however, cannot explain the presence of the small but reliable N400 effect to semantically primed versus unprimed masked targets that participants could neither categorize much above chance nor report (Stenberg et al. 2000).
