## 5 Conclusions  
The adjusted coefficient of determination in this study was 0.907, indicating that high explanatory power was obtained for the evaluation model. This result suggests that a \"good conversation\" is most negatively affected by \"quietness\". When the evaluation of \"quietness\" increased, that of a \"good conversation\" tended to decrease. Meanwhile, the evaluations of \"liveliness\", \"relaxation\", \"ease of communicating own voice to others\", and \"ease of talking\" had a positive influence on a \"good conversation\", and a \"good conversation\" tended to increase with increases in these evaluations. These findings suggest that the impression of a \"good conversation\" decreases in a sound environment that is too quiet when multiple people have discussions about knowledge creative activities and that a lively impression enhances the impression of a \"good conversation\". Moreover, these results suggest that high \"relaxation\" also leads to the impression of a \"good conversation\". As many people benefit from creative thinking, we hope that these results can be applied as widely as possible. However, our experimental participants were all Japanese and already engaged in creative work, and about 60% were adult university students. The findings of a previous meta-analysis [25] revealed that enhancing creativity may be more effective in organizational than in academic settings. However, in this study, no statistically significant difference was found in the evaluations because of differences in attributes between students and office workers. Therefore, it seems that the psychological evaluation model of a \"good conversation\" obtained in this study appropriately represents the evaluation structure of office workers. To enhance the generalizability of our findings, future research will be required to investigate the impact of occupations other than general construction and differences in official position, years of service, and cultural backgrounds. In addition, it is also necessary to investigate the types of sounds that are highly evaluated from the aspects of lively impression and relaxation. Conceptualization, S.T. and M.Y. ; methodology, S.T. and M.Y. ; software, M.Y. ; validation, S.T., M.Y. and T.O. ; formal analysis, S.T. ; investigation, S.T., M.Y. and T.O. ; resources, M.Y. ; data curation, S.T. ; writing--original draft preparation, S.T. ; writing--review and editing, M.Y. and T.O. ; visualization, S.T. ; project administration, M.Y. ; funding acquisition, M.Y. and T.O. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Although this study involves humans, it falls under the following items, which are listed as unnecessary criteria by the Bioethics Committee of the Faculty of Engineering, Ibaraki University. (1) Individuals cannot be identified under any conditions. (2) Experiments and surveys that are less invasive, and the principal investigator appropriately notices the risks, intimidation, and protection of personal information of the subjects. (3) Researchers do not request data collection from other institutions or companies (for example, research companies) that are not directly related to research. (4) There is no economic benefit relationship that affects the research results or the protection of the subjects. (5) Video and audio data are not collected. (6) It does not target groups (for example, those who have been bullied, children who do not attend school, persons with disabilities and their families, persons with mental illness, etc.) with characteristics that make them vulnerable to social pressure. (7) Questionnaire surveys, experimental stimuli, etc. do not include all question contents and items that exceed the range that can be experienced in social life or appear in the contents of daily conversation (for example, \"Have you ever been bullied?\", \"Have you had a recent libido?\", \"Have you ever wanted to die?\", etc.).