Cognitive load reduces visual identity negative priming by disabling the retrieval of task-inappropriate prime...

The present event-related potentials (ERP) study investigated the mechanisms by which cognitive load reduces the negative priming (NP) effect in a letter flanker task. On each trial, participants (N=20) first encoded a set of one to five digits, then responded to two successive flanker displays (prime, probe), and finally recalled a certain digit from the set. The flanker NP effect (i.e., increased probe RT when the prime distractor repeated as the probe target) was significant under low (1-2 items) but not high cognitive load (4-5 items). NP in the low-load condition was accompanied by left-anterior P2/N2 amplitude modulation which was also observed for prime-probe target repetitions and hence may reflect the processing of prime-probe similarity. Under high load, the P2/N2 effect was absent. It is suggested that cognitive load interferes with a retrieval-based mechanism in NP. Findings support episodic-retrieval explanations of visual identity-based NP.