Working with gaze-contingent displays requires minimizing the latency of the system (Loschky & Wolverton, 2007 (link); Saunders & Woods, 2014 (link)). Moreover, gaze-contingent manipulations of foveal vision call for eye-tracking equipment with high spatial accuracy and precision (Geringswald, Baumgartner, & Pollmann, 2013 (link)). Participants’ eye movements were recorded binocularly with an EyeLink 1000 Desktop mount system (SR Research, Ottawa, ON, Canada) with high accuracy (0.15° best, 0.25° to 0.5° typical) and high precision (0.01° root-mean-square [RMS]). The Eyelink 1000 was equipped with the 2000 Hz camera upgrade, allowing for binocular recordings at a sampling rate of 1000 Hz per eye. Stimuli were presented on a 21-inch CRT monitor with a refresh rate of 140 Hz at a viewing distance of 90 cm, taking up a 24.8° × 18.6° (width × height) field of view. A chin and forehead rest was used to keep the participants’ head position stable.
The experiments were programmed in MATLAB 2013a (The MathWorks, Natick, MA, USA) using the OpenGL-based Psychophysics Toolbox 3 (Brainard, 1997 (link); Kleiner, Brainard, & Pelli, 2007 ), which incorporates the EyeLink Toolbox extensions (F. W. Cornelissen, Peters, & Palmer, 2002 (link)). A game controller was used to record participants’ behavioral responses.
The experiments were programmed in MATLAB 2013a (The MathWorks, Natick, MA, USA) using the OpenGL-based Psychophysics Toolbox 3 (Brainard, 1997 (link); Kleiner, Brainard, & Pelli, 2007 ), which incorporates the EyeLink Toolbox extensions (F. W. Cornelissen, Peters, & Palmer, 2002 (link)). A game controller was used to record participants’ behavioral responses.
