## 6 Discussion  
In Experiment 1 (urban soundscapes) the stimuli were overall quite similar in character to the ones that [PERSON], [PERSON], and [PERSON] investigated [41]. This resulted in cross-correlations between perceptual ratings and acoustic variables showing similar patterns in the two studies, as can be seen by comparing [PERSON]'s Table II with our Tables 4 and 5. The predictive models in the two studies also resemble each other in terms of the variables included and the overall amount of variation explained, as can be seen by comparing [PERSON]'s Tables III and IV with our results from the first phase of the multivariate regression analysis, reported above. We believe that these parallels strengthen the modelling approach where soundscape indicators of different kinds are included, i.e., both acoustic and psychoacoustic measures, such as _loudness_, and categorical variables that describe more general characteristics. The latter might be a variable emanating from Technological/Human/Natural ratings or a categorical _type_ variable such as the one we determined in our initial selection of stimuli. In both Experiment 1 and Experiment 2, trait _emotional stability_ emerged as a significant predictor of _Pleasantness_. Low _emotional stability_ (i.e., more neurotic) was associated with high _Pleasantness_ ratings over and above soundscape _type_ and _loudness_. The predictive strength of this personality trait was similar in both soundscape contexts. Theory holds that neurotic individuals are sensitive to reward and punishment cues and that they are more prone to emotional contagion, i.e., their emotional state is more easily influenced by their appraisal of the environment [5]. Hedonic tone is a concept linked to a neurological mechanism that underpins reward and aversion behaviour, in such a way as to safeguard the individual against unpleasantness when arousal levels soar [54]. Consider also that participants in perceptual experiments may exhibit a tendency for response bias, i.e., to subconsciously adapt their rating in the direction they imagine is preferred by the experimenter. In the present study, those generally more sensitive to reward cues might have exhibited a demand bias, producing higher _Pleasantness_ ratings (discussed in e.g. [11; 12; 55]). Conversely, theory says that individuals who are more emotionally stable tend to use a wider range of emotion words expressing pleasure, thus emphasising the hedonic content of experiences [9]. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Trait** & **Experiment 2 (\(n=45\))** & **[15] (\(n=185\))** \\ \hline Extraversion & \(-0.43\) & \(-0.38\) \\ Agreeableness & \(0.05\) n.s. & \(0.25\) \\ Conscientiousness & \(0.46\) & \(0.34\) \\ _Emotional Stability_ & \(-0.10\) n.s. & \(-0.19\) n.s. \\ Openness & \(-0.17\) & \(-0.07\) n.s. \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Prediction of _noise sensitivity_ from Big Five traits for participants in Experiment 2. Note that [PERSON] used the neuroticism construct, which is considered the inverse of _emotional stability_. _Noise sensitivity_ correlated negatively with ratings of _Pleasantness_, which replicates previous findings [15] and is in line with the definition of the construct. Noise-tolerant participants were biased to rate the restaurant soundscapes as more pleasant. Inspection of the third plot in Figure 2 suggests that the relationship might not be linear. The optimum stimulation level theory [56] links evaluative perception of a stimulus to its information rate via a \(\cap\)-shaped relationship. Whether a similar mechanism is relevant to _noise sensitivity_ might be investigated in the future. The relationship between lower order _noise sensitivity_ and higher order broad personality characteristics is complex.