The present study examined the electrophysiological activity during the processing in the identification of signs. Participants performed a sign identification task, in which real, pseudo, and fake signs were adopted as stimuli. Common mathematical operation signs (e.g. +, −, ×, and ÷), which were known to the participants were adopted as the real signs. The pseudo signs had a similar appearance to the real signs (e.g.
, ×, and ÷). The fake signs were also unknown, but had an entirely different shape from the real signs (e.g.
). The behavioral results showed inferior recognition performance for pseudo signs relative to real or fake signs. Event-related potential results showed that (a) pseudo signs evoked a more positive P200 component than did real or fake signs, suggesting that more attentional resources might be allocated to the pseudo signs relative to the real or fake signs and (b) fake signs evoked a more negative N300 component than real or pseudo signs, suggesting that more cognitive resources might be recruited in processing the visual aspects for fake signs relative to real or pseudo signs. These results suggested that the P200 component, which is associated with attentional resource allocation, and the N300, which is sensitive to visual aspects, were evoked in processing the signs.