FM Tones

Frequency Modulated (FM) stimuli consisted of simple sinusoidal frequency modulated (FM) tones generated in MATLAB with a one second duration. FM was calculated as follows:
x(t)=Asin {2 π fc t + β sin(2 π fm t)}
where x(t) is the pressure variation over time t, A is the peak amplitude( or pressure), fc is the frequency of the carrier, β is the modulation index (equal to Δf/fm where Δf is the excursion from the carrier frequency) and fm is the modulation frequency (adapted from equation 2.5 in. (Plack & Carlyon, 1995) Frequency modulated (FM) tones, within the F0 range of typical prosodic utterances, were constructed by varying the fundamental/carrier frequency (F0) between 100 and 500 Hz in steps of 20 Hz. Modulation depths varied between 10 and 170 Hz (Davis Sample I) or 150 Hz (other samples) using steps of 10 Hz (Juslin & Laukka, 2001). A single modulation rate of 3 Hz was used in the first sample, and a modulation rate of 6 Hz was added for the other samples to form a more extensive 3-dimensional acoustic space.

Subjects listened to each stimulus and were asked to indicate which emotion was conveyed (between anger, fear, happiness, sadness, and no expression) and its emotional intensity (rated on a 7-point scale.)

Completion Time: 75-90 minutes
Dependent Variables: Emotion Category, Intensity Ratings

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References
Juslin, P. N., & Laukka, P. (2001). Impact of intended emotion intensity on cue utilization and decoding accuracy in vocal expression of emotion. Emotion, 1(4), 381–412. doi:10.1037//1528-3542.1.4.381
Plack, C. & Carlyon, R. (1995). Differences in frequency modulation detection and fundamental frequency discrimination between complex tones consisting of resolved and unresolved harmonics. Journal of Acoustical Society of America, 98, 1355-1364. doi: http://dx.doi.org/10.1121/1.413471