1. A method of single-trial detection of significant cognitive responses to stimuli, comprising: measuring EEG data of an operator's brain activity to stimuli from a plurality of electrodes placed on the operator's scalp; tracking the operator's free eye movement to determine fixation events; applying a fixation-locked window to the EEG data to generate a time segment of EEG data for each said fixation event; extracting one or more features from each time segment of EEG data; for each said fixation event, presenting said one or more features to a classifier to generate a fixation-locked cue as a likelihood output indicative of whether the operator exhibited a significant cognitive response to a presented stimulus; and outputting a sequence of the cues with a time code of the associated fixation event.