The effect of intensity on relative pitch

Abstract

In two experiments, we examined the effect of intensity and intensity change on judgements of pitch differences or interval size. In Experiment 1, 39 musically untrained participants rated the size of the interval spanned by two pitches within individual gliding tones. Tones were presented at high intensity, low intensity, looming intensity (up-ramp), and fading intensity (down-ramp) and glided between two pitches spanning either 6 or 7 semitones (a tritone or a perfect fifth interval). The pitch shift occurred in either ascending or descending directions. Experiment 2 repeated the conditions of Experiment 1 but the shifts in pitch and intensity occurred across two discrete tones (i.e., a melodic interval). Results indicated that participants were sensitive to the differences in interval size presented: Ratings were significantly higher when two pitches differed by 7 semitones than when they differed by 6 semitones. However, ratings were also dependent on whether the interval was high or low in intensity, whether it increased or decreased in intensity across the two pitches, and whether the interval was ascending or descending in pitch. Such influences illustrate that the perception of pitch relations does not always adhere to a logarithmic function as implied by their musical labels, but that identical intervals are perceived as substantially different in size depending on other attributes of the sound source.

Keywords:

• Relative pitch
• Intensity
• Looming
• Music cognition
• Interval size

Acknowledgments

This research was supported by the Australian Research Council discovery grant awarded to the first and fourth authors, DP0771890.

Notes

¹ Although direction accuracy was assessed merely to monitor lapses in attention, it was affected by the intensity of stimuli. Post hoc analyses of direction accuracy data (inverse reflected to address ceiling effects; see Tabachnick & Fidell, 1996, p. 83) revealed that direction judgements were more accurate for looming (M = 94.45%, SE = 1.41) than for fading (M = 90.90%, SE = 1.49) stimuli. For ascending intervals, accuracy was also better for high-static-intensity (M = 96.67%, SE = 1.03) than for low-static-intensity (M = 92.5%, SE = 2.57) stimuli; for descending intervals, the reverse was true (high static intensity: M = 89.03%, SE = 3.32; low static intensity: M = 96.25%, SE = 0.94). The analysis of direction accuracy data is available by request from W.F.T.

² We conducted a second analysis using rating data that were first normalized for each participant. All significant effects reported for the analysis of raw data were observed when data were normalized. These analyses are available by request from W.F.T.

³ Post hoc analyses of direction accuracy data (inverse reflected to address ceiling effects) revealed that for ascending intervals, direction accuracy was reliably better for looming (M = 87.22%, SE = 2.54) than for fading (M = 77.78%, SE = 2.89) stimuli; for descending intervals, the reverse was true (looming stimuli: M = 83.47%, SE = 2.83; fading stimuli: M = 90.00%, SE = 2.12). For static-intensity stimuli, accuracy was also better for high-intensity (M = 87.85%, SE = 2.00) than for low-intensity (M = 84.52%, SE = 2.11) stimuli and for descending (M = 89.31%, SE = 2.00) than for ascending (M = 83.06%, SE = 2.46) intervals. The analysis of direction accuracy data is available by request from W.F.T.

⁴ We conducted a second analysis using rating data that were normalized for each participant. All significant effects reported for the analysis of raw data were observed when data were normalized. These analyses are available by request from W.F.T.