However, with water sound and aeroplanes, they tend to show less sensitivity, indicated by the negative coefficient values. Visit frequency and length of stay are both peoples' behaviour characteristics. They are significantly related with 9 and 12
out of the 17 sounds, respectively. It is reasonable that the more frequently people come to the parks and the longer they stay there, the greater are the chances of hearing different sounds. However, length of stay seems to be more influential on experienced occurrence than visit frequency. It may indicate that peoples' sound sensitivity could be lowered by long term exposure to similar acoustic environment at a certain location. The relatively few and weak correlations between experienced occurrence of individual sounds and factors including education, occupation and residential status indicate that these three factors do not have much effect on people's sound sensitivity. There is generally no significant difference between males and females in terms of experienced occurrence of individual sounds, which is in agreement with former results in previous studies, where it was indicated that gender was not important in perception of individual sounds (Rylander et al., 1972;Fields, 1993; Miedema and Vos, 1999; Yang and Kang, 2005a; Yu and Kang, 2008).