Gaze-contingency paradigm

Because the display updates in response to the observer's eye movements, the gaze-contingency paradigm can be classified an interactive eye-tracking application.

[1] Over the past century, the way the eyes move in human activities as diverse as playing sport, viewing works of art, piloting aircraft, exploring visual scenes, recognizing face or facial expressions,[2][3] reading language, and sight-reading of music,[4] has revealed some of the ocular and psychological mechanisms involved in the visual system.

Indeed, due to an imperfect coupling between overt and covert attention,[5][6][7] it is not possible to exactly know which visual information the viewer is processing based on the fixation locations.

By controlling precisely the information projected in different parts of the visual field, the gaze-contingent techniques permit to disentangle what is fixated and what is processed.

The technical principle of the paradigm involves a computer interfaced with both an eye-movement tracking system (eye-tracker) and a display of the visual stimulus.

Successful gaze-contingency requires a fast computer, a display with a high refresh rate, and an eye tracker with low latency.

Parafoveal magnification paradigm: Graphical depiction of the parafoveal magnification paradigm (Miellet et al., 2009). The location of each fixation is indicated with an arrow and the corresponding display for that fixation is represented. Consecutive lines represent the chronological order of fixations.