Although working memory performance is predicted by the gating mechanism, which is part of attentional control, the attentional control effect on domain-specific matching processes in the 1-back task, is lack of neural evidence.

This study adopted event-related potential (ERP) technique, and employed both perceptual and conceptual matching conditions in a digital 1-back task, requiring to judge whether the current number was perceptually or quantitatively identical to the prior one. Three types of number pairs were adopted: shape/value match (S + V +, e.g., ‘3 3’ or ‘三 三’), shape mismatch/value match (S − V + , e.g., ‘3 三’ or ‘五 5’) and shape/value mismatch (S − V − , e.g., ‘3 5’ or ‘五 三’).

The ERP results showed that both S − V + and S − V − elicited similar larger P2 amplitudes and longer N2 and P3 latencies than S + V + in both conditions, reflecting the gate opening for perceptual input. Moreover, a task-relevance effect on P3 amplitudes was observed, with a deflection for S − V − in the conceptual matching condition and for S − V + and S − V − in the perceptual matching condition, suggesting that the gating opening mechanism enabled the retrieval of relevant information.

Hence, the matching effect on P3 supported the gating opening mechanism on the matching subprocess underlying the N-back task.