Pure Emotion-loaded Materials in the International Affective Digitized Sounds (IADS): A Study on Intensity Ratings in Chinese University Students

Background: Materials loaded with pure emotion are essential for basic and clinical research on sounds. The International Affective Digitized Sounds (IADS) is one of the widely-used emotional tools, but its materials are not clearly labeled with specific emotions. We have hypothesized that the IADS contains pure vectors of at least disgust, erotica (or erotism), fear, happiness, sadness and neutral emotions. Methods: We therefore selected 48 IADS sounds with saturate emotions, and invited 271 male and 353 female university students to rate the intensity of the emotions conveyed in each sound. The ratings were then analyzed with the exploratory and confirmatory factor analyses. Results: Five factors were observed, namely: erotica, fear-sadness, happiness, neutrality, and disgust. Later, as two facets, sounds of fear-sadness were separated. Thirty sounds under six facets were finally retained with good model-fit indices and satisfactory factor internal reliabilities. Moreover, males scored significantly higher on erotica than females did. Conclusion: Our study purified a series of emotion-loaded IADS sounds, which might help clarify the pure effects of sound emotion in future research and clinical management of affective disorders.