Early detection of a deficit in vigilant attention can allow for user notification or intervention. In this paper, Electrophysiological correlates of vigilant attention from a random-dot motion task were explored. Using only frontal (Fz) and parietal (Pz) EEG channels, spectral features of response time were determined. Notably, significant differ-ences in high-beta, gamma and alpha frequency bands were found between fast and slow reaction times. These results are interpreted in line with the relevant literature on arousal, off-task thought and active visuospatial attentional suppression. The presence of response-locked time-domain features was analysed. However, motor-related features obfuscated these features.