## 5 Conclusions  
In this study, the influence of a particular contextual factor--the viewpoint of a park visitor on tranquility--on the perception of the sonic environment was investigated. To extract the viewpoint on tranquility, the results from an earlier study about the meaning of \"_zones calmes_\" (quiet areas) [16] were translated to a set of 13 most differentiating statements. A survey with 660 participants in eight urban parks in Antwerp was used to relate these viewpoints to different aspects of the soundscape. The results obtained in this work show a tendency to falsify the first hypothesis stated in the introduction. Persons associating tranquility to hearing natural sounds do not tend to notice natural sounds more during their visit to a park. Moreover, the trend between belonging to this viewpoint group and hearing natural sounds is slightly but statistically significantly negative. Therefore, persons adhering to the \"Natural sound sources\" viewpoint notice less natural  
Figure 3: Membership of tranquility viewpoint groups, as a function of the response to the direct question on park purpose: (**A**) percentages of people responding to an opinion statement in each tranquility group; (**B**) relative membership to tranquility group per opinion on the park purpose. In (**B**): whiskers correspond to one standard error, and stars indicate statistically significant difference confirmed by analysis of variance between tranquility groups. sounds than their peers, and, thus, it is expected that they do not pay more attention to the natural sounds. However, no statistically significant trend was found between noticing human sounds and belonging to the tranquility viewpoint \"Social relationships\". In turn, this result neither confirms nor falsifies the first hypothesis. Turning to the second hypothesis: non-expected sounds are likely to be noticed more often than the expected ones. The results demonstrate that indeed people more frequently notice and report hearing sounds other than the ones associated with their tranquility viewpoint. In particular, it was found that the participants who belong to groups that associate tranquility to natural sound sources or to silence were more often found amongst those that reported hearing mechanical sounds a lot, and that there was a statistically significant positive trend for belonging to these tranquility viewpoint groups and noticing mechanical sounds. On the other hand, persons belonging to the tranquility viewpoint group \"Social relationships\" do not hear mechanical sounds more often. In addition, we hypothesized that the people who notice these unexpected sounds would also assess soundscapes as less pleasing. In turn, statistically significant trends were found for people who associate tranquility to natural sound sources or to silence and their rating of the overall quality of the sonic environment. Therefore, people seem to pay more attention to the sounds that they do not expect to hear and rate the quality of the sound environment in Antwerp parks as less pleasing. The role of expectation is confirmed by the statistically significant negative trend between the answer to a direct question on whether the sounds that were heard matched the person's expectation and their membership to tranquility viewpoint groups \"Natural sound sources\" and \"Silence\". All of these aforementioned results confirm the statements in the second hypothesis. Our study also showed that there is no one-to-one relationship between the viewpoint on tranquility as assessed using the proposed 13 statements and the response to a direct question on the purpose of an urban park in general. Specifically, most of the people reported a park as a place for appreciating nature. However, no statistically significant difference between the membership to tranquility groups was found. On the other hand, people that see a park as a place for appreciating silence belong to the \"Silence\" tranquility viewpoint group statistically significantly more often.