# A Study on Ergonomic Layout of Automotive Electronic Shift Buttons
## 4 Discussion
Therefore, to summarize the aforementioned results, among the six layouts (L1, L2, L3, L4, L6, and L9) that received high marks in _Research activity 1-1_, L3, to which the consistency, functional similarity, and stereotype principles that were found to be important in _Research activity 1-2_ were applied altogether, can be recommended as the most ergonomic layout. However, the results of _Research activity 2-1_ indicated that the shift button layout evaluation differed considerably depending on driving experience. In _Research activity 2-1_, in the case of the novice driver group, L1, L2, L3, and L4 showed higher scores than 4 (\"Neutral\") for all 7 measures and higher mean scores than L5, L7, L9, L10, L11, and L12, with statistical significance in some of the pairwise comparisons (Figure 2). In the experienced driver group, L1, L3, and L9 received higher scores than 4 (\"Neutral\") for all 7 measures and higher mean scores than L2, L4, L5, L7, and L10, with statistical significance in some of the pairwise comparisons (Figure 3). The five layouts that received high marks in the novice or experienced driver groups (L1, L2, L3, L4, and L9) were among the layouts that received high marks from all respondents in _Research activity 1-1_; thus, it can be confirmed that the stereotype principle was applied to these five layouts. Interestingly, L6, which received high marks in _Research activity 1-1_, did not show superiority compared to the other layouts in both groups in _Research activity 2-1_. Given that L6 was a layout to which only the stereotype principle was applied, these results suggest that, despite the importance of the stereotype principle, it is preferable to apply it in combination with other principles rather than alone. This result is consistent with the fact that L8, to which only the stereotype principle was applied, was not superior to the other layouts in both groups. Future studies may consider various layouts to which only the stereotype principle is applied to enhance the understanding of the effects of that principle. For both the novice and experienced driver groups, L1 and L3 received high scores in _Research activity 2-1_. The consistency and stereotype principles were applied to both the layouts, and the functional similarity principle was applied to L3. In contrast, for L2, L4, and L9, conflicting results were obtained from the novice and experienced driver groups. The compatibility principle (instead of the consistency principle) was applied to L2 and L4, which received high marks only in the novice driver group, whereas the consistency principle (instead of the compatibility principle) was applied to L9, which received high marks only in the experienced driver group. These conflicting results between the groups are also displayed in Table 7. Here, L2 and L4, to which the compatibility principle was applied, received higher scores in the novice driver group than in the experienced driver group. In contrast, L9, to which the consistency principle was applied, received higher marks in the experienced driver group than in the novice driver group. L11, to which the consistency principle was applied, also received higher marks in the experienced driver group than in the novice driver group, although it was not among the five layouts that received high marks in the novice or experienced driver groups (L1, L2, L3, L4, and L9). These findings suggest that the compatibility principle may be more significant for novice drivers, whereas the consistency principle may be more significant for experienced drivers. Indeed, 5 of the 10 respondents in the experienced driver group stated that it would be desirable to swap the positions of the D and R buttons (i.e., to change the order to P-R-N-D by applying the consistency principle instead of the compatibility principle) to improve L2. In addition, in the case of L4, 6 of the 10 respondents in the experienced driver group stated that it was necessary to change the order of the shift buttons.