Question: What cognitive features are used?
Answer: Readability (RED),  Number of Words (LEN), Avg. Fixation Duration (FDUR), Avg. Fixation Count (FC), Avg. Saccade Length (SL), Regression Count (REG), Skip count (SKIP), Count of regressions from second half
to first half of the sentence (RSF), Largest Regression Position (LREG),  Edge density of the saliency gaze
graph (ED),  Fixation Duration at Left/Source
(F1H, F1S),  Fixation Duration at Right/Target
(F2H, F2S),  Forward Saccade Word Count of
Source (PSH, PSS),  Forward SaccadeWord Count of Destination
(PSDH, PSDS), Regressive Saccade Word Count of
Source (RSH, RSS),  Regressive Saccade Word Count of
Destination (RSDH, RSDS)