Effects of premature lure stimuli on 2nd-target identification in rapid serial visual presentation: inhibition induced by lures or by 1st target?

In many rapid serial presentation tasks, two targets ("T1" and "T2") have to be distinguished from background stimuli. Here, digits ("lures") were interspersed among the background letters, differing from the T2 digit by occurring before rather than after T1. The resulting inhibitory effects on T2 identification may either be evoked directly by the lures or be triggered by T1, interfering with positive priming of lures on T2. To distinguish between these two alternatives, lures, T1, and T2 were presented in two different simultaneously running streams, T2 was or was not the same digit as a lure, and EEG potentials related to lures, T1, and T2 were recorded. Effects on T2 identification better fit the view that lures exerted positive priming interrupted by T1. Recurrence of lures in the trial led to abridged duration of the lure-evoked N2pc, and T2-evoked N2pc was reduced after lures. Also these N2pc effects may reflect positive priming.