# Analysis of the Learning Process through Eye Tracking Technology and Feature Selection Techniques
## Materials and Methods
### Data Analysis  
#### 2.4.1 Statistical Study  
A study was conducted using three-factor fixed effects analysis of variance (ANOVA) statistical techniques (type of participant, i.e., student vs. teacher, age (over 50 years old vs. under 50 years old) and knowledge (expert vs. novices)) and eta squared effect value analysis (\(\eta^{2}\)). Analyses were performed with the SPSS v.24 statistical package [55].  
Figure 1: Calibration with eye tracking.  
Figure 2: Watching the video and carrying out the crossword puzzle. Note. The circles on the image on the right indicate each point of fixation of the learner on each element in the visual tracking sequence of the image.  
A 2 \(\times\) 2 \(\times\) 2 factorial design (experts vs. non-experts, students vs. teachers, age (over 50 years old vs. under 50 years old)) was used [34]. The independent variables were type of participant (experts vs. novice), age (over 50 years old vs. under 50 years old) and participant type (students vs. teachers). The dependent variables were as follows:  
* Solving crossword puzzle results;
* Fixations (fixation count, fixation frequency count, fixation duration total, fixation duration average, fixation duration maximum, fixation duration minimum, fixation dispersion total, fixation dispersion average, fixation dispersion maximum, fixation dispersion minimum);
* Saccades (saccade count, saccade frequency count, saccade duration total, saccade duration average, saccade duration maximum, saccade amplitude total, saccade amplitude average, saccade amplitude maximum, saccade velocity total, saccade velocity average, saccade velocity maximum, saccade latency average);
* Blinks (blink count, blink frequency count, blink duration total, blink duration average, blink duration maximum, blink duration minimum) and scan path length.  
These metrics are related to the analysis of the cognitive procedure during visual tracking. This procedure is based on the stimulus-processing-response structure. Information enters via the visual pathway (retina-fovea) and is processed at the level of subcortical and cortical regions within the central nervous system. This processing results in a sensory stimulation response. Specifically, saccades constitute a form of sensory-to-motor transformation in response to a stimulus that has been found to be significant and a sensorimotor control of the processing. Saccadic eye movements are used to redirect the fovea from one point of interest to another. Likewise, fixation is used to keep the fovea aligned on the target during subsequent image analysis. This alternating saccade-fixation behaviour is repeated several hundred thousand times a day in humans and is central to complex behaviours such as reading. Saccades can be triggered by the appearance of a visual stimulus that is motivating to the subject or initiated voluntarily by the person's interest in a particular object. Saccades can be suppressed during periods of visual fixation, in which case the brain must inhibit the automatic saccade response [37]. The whole process is summarised in Figure 3. In addition, a video ([[https://youtu.be/DIRK21](https://youtu.be/DIRK21) afGgo]([https://youtu.be/DIRK21](https://youtu.be/DIRK21) afGgo) access on 28 June 2021) on the process of performing the task applied in this study can be consulted. In this video, the fixation and saccade points can be seen.  
Figure 3: Visual tracking process during the resolution of a task.