FIGURE. Box plots with quartiles (upper values75%,median50%, and lower values 25%) for the attach slope and spectral centroid in each stimulus category. Outliers and extreme values are excluded.
Happy music with lyrics had significantly faster attack slopes than sad music with and without lyrics(T >3, p <0.002). However, happy or sad music with lyrics did not differ in attack slopes from happy or sad music without lyrics (p >0.07), and happy music without lyrics did not differentiate in the attacks lopes from sad music with or without lyrics (p >0.1).
Brattico, E., Alluri, V., Bogert, B., Jacobsen, T., Vartiainen, N., Nieminen, S., & Tervaniemi, M. 2011. A Functional MRI Study of Happy and Sad Emotions in Music with and without Lyrics. Frontiers in Psychology, 2: 308.