## 4 Results and Discussion
### Noticing Sounds  
Relative membership to tranquility viewpoint (Equation (4)) was evaluated to observe how tranquility viewpoint affects people's perception of soundscape. Since previous work ([PERSON] et al., 2010; [PERSON] et al., 2011; [PERSON] et al., 2011) has found a strong relationship between the sounds that people report to have heard while in a public place and the pleasantness of the soundscape, the relationship between the sounds that people have heard and their membership to a tranquility viewpoint group was assessed first. For brevity, the fact that people reported that sounds belonging to a specific category (mechanical, natural, human) have been frequently heard is labeled as noticing these sounds. Survey participants answered the question about hearing different categories of sound on a 5-point ordinal category scale. The calculated membership to tranquility viewpoint groups is furthermore assessed as a continuous variable as it aggregates the answers from an 11-point scale and 13 questions with an overlap integral method (Equation (2)). In Figure 2, the results are therefore shown as the relative membership to tranquility viewpoint groups, i.e., the average of the normalized degree of similarity calculated by Equations (3) and (4), for different answer categories on the questions about hearing particular sounds. This may look slightly unconventional, as it is more popular to show expected effects as a function of expected cause. Given that the descriptive analysis shows some possible trends, the statistical significance was assessed using the Kendall rank correlation coefficient (\(\tau_{b}\)) (statistical analyses were performed using the Python programming language with _Scipy_[33] (analysis of variance (ANOVA) and correlation) and _Statsmodels_[34] (Tukey test) modules). Table 2 shows this correlation coefficient between noticing sounds belonging to one of the three categories (human sounds, natural sounds, mechanical sounds) and the relative adherence to the tranquility viewpoint groups (\"Social relationships\", \"Natural sound sources\", \"Silence\"). Belonging to the tranquility viewpoint group \"Social relationships\" (first row in Table 2) does not correlate statistically significant with noticing sounds from any of the categories, yet there is a weak trend for noticing more human sounds. However, the trends between belonging to the tranquility viewpoint group \"Natural sound sources\" and noticing natural sound (negative) and noticing mechanical sounds (positive) are highly statistically significant. Likewise, the positive trend between belonging to the tranquility viewpoint \"Silence\" and noticing mechanical sounds is statistically significant, while the negative trend between belonging to the tranquility viewpoint \"Silence\" and noticing natural sounds is statistically significant but also weaker. Finally, there is no statistically significant or pronounced trend between belonging to either of these last two tranquility viewpoint groups and noticing human sounds. Figure 2: Relative membership to tranquility viewpoint groups shown in relation to hearing sound sources: (**A**) human, (**B**) natural and (**C**) mechanical. In (**D**): relative membership in relation to evaluation of the quality of the sonic environment is presented. Whiskers indicate one standard error of the dataset. A star indicates statistically significant difference confirmed by the analysis of variance between tranquility groups within one answer category. Rank correlation only allows detecting monotonous trends. Although these already illustrate the main effect, visual inspection of Figure 2 seems to reveal that less people associating tranquility to social relationships report hearing human and mechanical sounds \"very much\". Only the latter is confirmed by a one-way ANOVA test: there is a statistically significant difference between the participants belonging to different tranquility groups who reported hearing mechanical sounds \"very much\" (\(F\)(2,168) = 5.969, \(p\) = 0.003).