09-07-2020, 04:43 AM
The EyeLink online parser identifies saccades and fixations using a method called "saccade picking." This approach works by constantly monitoring the eye's speed (velocity) and change in speed (acceleration).
Think of it like a speed limit for the eye; any movement that exceeds a set threshold is classified as part of a saccade, while anything below it is considered part of a fixation.
Standard Thresholds
By default, the parser uses the following thresholds:
Based on this method, a fixation is defined by the saccades that surround it:
Think of it like a speed limit for the eye; any movement that exceeds a set threshold is classified as part of a saccade, while anything below it is considered part of a fixation.
Standard Thresholds
By default, the parser uses the following thresholds:
- Velocity Threshold: 30°/s
- Acceleration Threshold: 8000°/s²
Based on this method, a fixation is defined by the saccades that surround it:
- A fixation begins the moment the preceding saccade ends (when eye velocity and acceleration drop below the thresholds).
- A fixation ends the moment the subsequent saccade begins (when eye velocity and acceleration rise above the thresholds).