In experiments 3 and 4, response functions were measured under varying levels of blur applied equally to each of the half-images. As for the contrast experiments, blocks of 10 trials were run at a given blur level, and the order of blocks was randomized across participants. In experiment 3 (N = 15; average age 24 years, eight females, one EEG session per participant), disparity response functions were measured for disparity plane, 0.5-cpd, and 1.2-cpd grating conditions with 0, 1.37, and 4.1 arcmin of blur, using sweep ranges of 0.5 to 8 arcmin for the plane and 1.2-cpd grating and a sweep range of 0.2 to 6 arcmin for the 0.5-cpd disparity grating.
In experiment 4 (N = 15; average age 26 years, 10 females, one EEG session per participant), disparity response functions were measured with a larger range of blur values. Responses to the disparity plane were measured with 0, 6.07, and 12.13 arcmin of blur using sweep ranges of 0.5 to 8, 0.75 to 12, and 0.75 to 12 arcmin disparity, respectively. Responses to a 0.5-cpd disparity grating were measured at 0, 3.03, and 6.07 arcmin of blur using sweep ranges of 0.2 to 6, 0.2 to 6, and 0.5 to 8 arcmin disparity. Responses to a 1.2-cpd disparity grating were measured at 0, 3.03, and 6.07 arcmin of blur using sweep ranges of 0.5 to 8, 0.75 to 12, and 0.75 to 12 arcmin disparity. Sweep ranges were shifted between conditions to optimally capture the variation in the response amplitude across different blur levels.