## 4 Discussion
It is therefore recommended that a multidimensional approach with different eye-tracking parameters, as well as measurement methods, be utilized in future research. Additionally, incorporating a questionnaire with open-ended questions into the study design is deemed to be beneficial. This approach facilitates the collection of feedback regarding both the methodology and the various design elements [78]. A further significant limitation pertains to the quality of the eye-tracking data, specifically the discarding of four sets of eye-tracking data from the final sample. The duration of the two runs of the pair comparison was limited to a maximum of 15 min, and a thorough examination revealed indications of participant fatigue, as well as issues related to inaccurate calibration and the use of make-up, which resulted in poor data quality. The issue of fatigue was evidenced by prolonged periods during which participants exhibited closed eyes. Such factors must be considered in future investigations. Another limitation of the study was the presentation of the buttons in isolation from any contextual framework. The buttons were solely presented as shapes and lacked any labels. This was because an abstract initial study of attentional allocation without distraction was to be conducted. It is conceivable that the evaluation of these buttons might vary if they were to be labeled or viewed within a contextual framework, as is usually the case with graphical user interfaces. This is a possibility that will be examined in subsequent research. It is noteworthy that [PERSON] et al. [65] presented their buttons in the context of a radio screen of a multimedia display in a vehicle and obtained similar results. At this point it is worth noting that [PERSON] et al. [65] presented their buttons in the context of a radio screen of a multimedia display in a vehicle and obtained similar results. The measurement of salience also constitutes a limitation of this study. Preference and the visual attention distribution were measured. Based on the results presented and the existing literature, it can be inferred that the rankings may also reflect the salience of the buttons, as visually salient objects are more likely to be chosen [77]. However, this assumption should be validated through a more detailed analysis of the eye-tracking data. The initial gaze could serve as a useful metric for this purpose, as demonstrated in the work by [PERSON] et al. [2]. Additionally, it is advantageous to evaluate the salience of design elements subjectively. The findings of this study may provide valuable insights for the future design of graphical user interfaces (GUIs). Notably, clear results were observed for the fifth-ranked version of the completely square button. This button version did not receive the highest visual attention, nor was it preferred or perceived as particularly aesthetically pleasing compared to other button designs. However, these results should be interpreted with caution, as the button versions need to be tested in an appropriate context before specific design recommendations for GUIs can be made. Future research will extend this work to include an analysis of the salience of design elements in relevant contexts. In the context of future research, the utilization of a combination of pairwise comparisons, eye-tracking, and interviews emerges as a promising avenue for exploration. This approach would facilitate the selection of two GUIs, each characterized by distinct design elements, by users. Moreover, the integration of eye-tracking data and interview responses would enable the extraction of insights into the rationale underlying user decisions. Additionally, it is imperative to undertake a comprehensive examination of the influence of both primary and secondary tasks in conjunction with GUIs, with a view to elucidating the salience of design elements.