# Vehicle Politeness in Driving Situations
## 4 Results
### Hypothesis Testing  
A two-way multivariate analysis of variance (MANOVA) was conducted to assess the main effects of polite strategies in different situations on interaction experience. A multivariate test confirmed the validity of the research model. Politeness strategy in normal events had significant main effects on interaction experience, \(F(7,46)=4.07\), \(p<0.01\), \({\eta_{p}}^{2}=0.38\), for all test results (i.e., [PERSON] lambda = 0.618, [PERSON]'s trace = 0.382, [PERSON]'s trace = 0.619, [PERSON]'s largest root = 0.619). In failure situations, the tests (i.e., [PERSON] lambda = 0.656, [PERSON]'s trace = 0.344, [PERSON]'s trace = 0.525, [PERSON]'s largest root = 0.525) also revealed significant main effects, \(F(7,46)=3.45\), \(p<0.01\), \({\eta_{p}}^{2}=0.34\), for all measured variables. The interaction effect between vehicle politeness in different situations was not significant, \(F(7,46)=2.15\), \(p<0.1\), \({\eta_{p}}^{2}=0.25\), when considering all variables together (i.e., [PERSON] lambda = 0.754, [PERSON]'s trace = 0.246, [PERSON]'s trace = 0.326, [PERSON]'s largest root = 0.326). Still, polite strategy in different situations may influence each other in specific interaction experience. Including the interaction effects, the main effects of vehicle politeness in respective events on each experience were tested for drawing detailed implications. Figure 3: Interaction Experience of Each Instruction Strategy. Table 1 shows the main effects of politeness strategy on each experience in different situations. In normal events, in which the vehicle functions appropriately, polite instruction strategy was found to enhance the interaction experience. Drivers felt a stronger social presence from a polite vehicle in normal events, \(F(1,52)=9.65\), \(p<0.01\), \({\eta_{p}}^{2}=0.16\). They also evaluated the vehicle as more polite, \(F(1,52)=4.42\), \(p<0.05\), \({\eta_{p}}^{2}=0.08\), when it gave polite instructions in that events. In addition, drivers were more satisfied while driving with the vehicle of employing politeness strategy in normal events, \(F(1,52)=5.42\), \(p<0.05\), \({\eta_{p}}^{2}=0.09\) and showed a higher intention to use the vehicle, \(F(1,52)=4.66\), \(p<0.05\), \({\eta_{p}}^{2}=0.08\). There were no significant differences in openness, attractiveness, ease of use for polite instructions in normal events. In failure situations, however, politeness strategy could not enhance the interaction experience. Instead, it hindered the experience in some respects. Openness of requests was decreased by vehicle politeness in failure events, \(F(1,52)=8.32\), \(p<0.01\), \({\eta_{p}}^{2}=0.14\). It shows that drivers were somewhat reluctant to follow polite instructions in failure events. They also felt more difficulty in using the vehicle which provided polite instructions in failure events, \(F(1,52)=4.25\), \(p<0.05\), \({\eta_{p}}^{2}=0.08\). Other experience aspects were not influenced by vehicle politeness in failure events. Table 1 also shows the interaction effects of politeness strategy in respective events on specific experience variables. With regard to attractiveness and ease of use, polite instructions showed different effects depending on situations (see Figure 4). Politeness instructions improve the interaction experience aspects of attractiveness and ease of use. The enhanced effects, however, only worked when the vehicle employed plain instructions in failure events. Applying politeness strategy in failure events cancelled out the effects or changed the effects to negative directions (e.g., attractiveness, ease of use). The results indicate the limited validity of the proposed research model. Vehicle politeness improves interaction experience in normal working situations while impeding the experience in failure situations. With the results, hypothesis 1 is partially accepted and hypothesis 2 is not confirmed.