Eye-tracking data processing and analysis
blinks
EVENTS, EVENT
The researcher analyzing the eye-tracking and EEG data sets (JW) was not involved in data collection and was blinded to the participants’ identities. A parsing system incorporated in the EyeLink 1000 software intersected the raw eye position data into visual events, i.e., saccades, fixations, and blinks. This event data set was analyzed in the statistical computing program R (Saccade latency was defined as the time from stimulus onset to the start of the first saccade regardless of whether the saccade was elicited in the correct direction. A directive error was defined as a saccade towards lateral stimuli, i.e., a prosaccade. Trials were removed from further analysis when i) the latency was in the anticipatory range (<90 ms) or longer than two standard deviations from the individual mean latency of the participant, ii) the first saccade after stimulus onset had a starting position >3° lateral of the central fixation cue, iii) a saccade with an amplitude smaller than 0.5° or >15° was executed or iv) a blink occurred between stimulus presentation and the first saccade. Processing of the eye-tracking data led to the rejection of a total of 16.8 % ± 11.5 % of all recorded trials (off: 19.7 % ± 14.3 %; 130 Hz: 14.4 % ± 11.3 %; 60 Hz: 16.2 % ± 8.6 %, χ2(2, 13) = 3.964, p = 0.1).