Signal Detection tasks typically involve within-subject signal changes. Such a procedure does not lend itself to event-related potential (ERP) experiments where the need for averaging necessitates the maintenance of consistent stimulus parameters. In the present ERP study we adopt a novel approach to thresholding that allows within-subject signal manipulation. The Signal Detection task required the identification of letter targets, formed from dots, in a random dot field. ERP waveforms were segmented into three windows corresponding to N1, N2, and P300 components. Analysis shows that ERP variations are dependent on both task demands and response characteristics for N1, N2, and P300 components.