Setting sights higher: category-level attentional set modulates sustained inattentional blindness

Previous research has shown that inattentional blindness is modulated by how people tune their "attentional set": the more featurally similar the unexpected object is to what people are trying to attend, the more likely it is that they will notice it. The experiments in this paper show that people can also establish attentional sets based on semantic categories, and that these high-level attentional sets modulate sustained inattentional blindness. In "Experiment 1", participants tracked four moving numbers and ignored four moving letters or vice versa, and the unexpected object was either a capital letter 'E' or its reverse, a block-like number '3'. Despite their featural similarity, participants were more likely to notice the unexpected object belonging to the same category as the tracked objects. "Experiment 2" replicated this effect in conditions where the unexpected object possessed a unique luminance and was less likely simply to be confused with other display items.