## 4 Results and Discussion
### Shap Analysis across 49 Features
#### 4.2.2 Results for Quadrant 1  
In Figure 4, we observe that 'Max Saccade Length', which represents the amplitude of saccades, is the most significant feature for predicting emotions in Quadrant 1 of the CMA, associated with low arousal and positive valence, indicative of emotions such as relaxation and calmness. A higher value of this feature positively influences the model's predictions, suggesting that individuals experiencing these emotions tend to exhibit longer saccades. This indicates that during states of calmness and relaxation, the eye travels greater distances between fixation points. Similarly, higher values of 'SD Saccade Length' and 'Mean Saccade Length' also affect the model's output in a positive way. The figure also shows that an increased 'Number of Saccade' impacts the model generally in a positive way, but in some cases, it has a negative impact. This variability suggests that the number of saccades alone does not consistently indicate specific emotions  
Figure 4: Summary Plot of the First 10 Features for Quadrant 1. (For a complete view of all 49 features, visit: [[https://doi.org/10.6084/m9.figshare.26130589](https://doi.org/10.6084/m9.figshare.26130589)]([https://doi.org/10.6084/m9.figshare.26130589](https://doi.org/10.6084/m9.figshare.26130589)) (accessed on 10 July 2024)). Figure 3: Variations in F1-Score across different feature numbers for Quadrant 0.  
within Quadrant 1. Additionally, higher values for 'Max Saccade Amplitude', 'SD Saccade Amplitude', and 'Mean Saccade Amplitude' positively affect the model, reinforcing the observation that larger saccadic movements are characteristic of individuals feeling positive and relaxed. Further analysis reveals that lower values of 'Skew Fixation Duration', 'Max of Fixation Duration', 'SD Fixation Duration', and 'Mean Fixation Duration' negatively impact the model's predictions. Conversely, higher values in these fixation duration metrics are associated with states of calmness or relaxation. This pattern supports the hypothesis that during relaxed states, individuals tend to have longer fixation durations, indicating fewer eye movements and a more stable gaze. Figure provides insight into the role of blinking-related features in the model's predictions for Quadrant 1 of the CMA, which is associated with emotions such as relaxation and calmness. The data show that lower values for 'Skew Blink Duration' and 'Max Blink Duration' negatively influence the model, suggesting that shorter blink durations do not correspond with the emotional states typical of this quadrant. Conversely, longer blink durations are more indicative of relaxation and calmness. Additionally, 'Number of Blink' and 'Standard Deviation of Blink Duration' demonstrate minimal influence on the model, leading to negligible changes in SHAP values, indicating their limited diagnostic value for emotions in this quadrant. Figure provides insight into the role of blinking-related features in the model's predictions for Quadrant 1 of the CMA, which is associated with emotions such as relaxation and calmness. The data show that lower values for 'Skew Blink Duration' and 'Max Blink Duration' negatively influence the model, suggesting that shorter blink durations do not correspond with the emotional states typical of this quadrant. Conversely, longer blink durations are more indicative of relaxation and calmness. Additionally, 'Number of Blink' and 'SD Blink Duration' demonstrate minimal influence on the model, leading to negligible changes in SHAP values, indicating their limited diagnostic value for emotions in this quadrant. Further analysis in Figure 5 demonstrates the benefits of feature selection. Employing only the top 12 most important features instead of the full set of 49 results in an enhanced model performance with an F1-score of 0.95.