Pitch perception and production in congenital amusia: Evidence from Cantonese speakers

Abstract

This study investigated pitch perception and production in speech and music in individuals with congenital amusia (a disorder of musical pitch processing) who are native speakers of Cantonese, a tone language with a highly complex tonal system. Sixteen Cantonese-speaking congenital amusics and 16 controls performed a set of lexical tone perception, production, singing, and psychophysical pitch threshold tasks. Their tone production accuracy and singing proficiency were subsequently judged by independent listeners, and subjected to acoustic analyses. Relative to controls, amusics showed impaired discrimination of lexical tones in both speech and non-speech conditions. They also received lower ratings for singing proficiency, producing larger pitch interval deviations and making more pitch interval errors compared to controls. Demonstrating higher pitch direction identification thresholds than controls for both speech syllables and piano tones, amusics nevertheless produced native lexical tones with comparable pitch trajectories and intelligibility as controls. Significant correlations were found between pitch threshold and lexical tone perception, music perception and production, but not between lexical tone perception and production for amusics. These findings provide further evidence that congenital amusia is a domain-general language-independent pitch-processing deficit that is associated with severely impaired music perception and production, mildly impaired speech perception, and largely intact speech production.

FIG. 1.

(Color online) Time-normalized F₀ contours (in Hertz, or Hz) of the four tone pairs used in the perception tasks: (A) bei22 [鼻, “nose”] - bei33 [臂, “arm”]; (B) jyu23 [雨, “rain”] - jyu25 [鱼, “fish”]; (C) min21 [綿, “cotton”] - min22 [麵, “noodle”]; (D) tong25 [糖, “sweet (candy)”] - tong55 [湯, “soup”]. Note: 22, 33, 23, 25, 21, and 55 correspond to the Cantonese low-level (Tone 6), mid-level (Tone 3), low-rising (Tone 5), high-rising (Tone 2), low-falling (Tone 4), and high-level (Tone 1) tones, respectively.

FIG. 2.

Performance (in d′) of the 16 amusics and 16 controls in the tone perception tasks: (A) speech condition, and (B) non-speech condition. Note: Tone21_22 stands for the stimulus pairs containing Tone21 and/or Tone22 either in “same” (Tone21-Tone21; Tone22-Tone22) or “different” (Tone21-Tone22; Tone22-Tone21) conditions, and the same is for Tone22_33, Tone23_25, and Tone25_55.

FIG. 3.

(Color online) Mean time-normalized F₀ contours (in z-score normalized log F₀) of the six Cantonese tones (A–F) produced by amusics and controls, averaged across 16 participants in each group. Note: Tone55, Tone25, Tone33, Tone21, Tone23, and Tone22 correspond to the Cantonese high-level (Tone 1), high-rising (Tone 2), mid-level (Tone 3), low-falling (Tone 4), low-rising (Tone 5), and low-level (Tone 6) tones, respectively. Grey error bars reflect standard error.

FIG. 4.

Tone production accuracy (in percentage of correct responses) of 16 amusics and 16 controls as judged by 8 native listeners. Note: Tone21, Tone22, Tone23, Tone25, Tone33, and Tone55 correspond to the Cantonese low-falling (Tone 4), low-level (Tone 6), low-rising (Tone 5), high-rising (Tone 2), mid-level (Tone 3), and high-level (Tone 1) tones, respectively.

FIG. 5.

Boxplots of singing ratings of 16 amusics and 16 controls as evaluated by 8 Cantonese listeners (A) by provided guidelines and (B) based on intuition. The accuracy rating guidelines (1–8) were developed by Wise and Sloboda (Anderson et al., 2012; Wise and Sloboda, 2008). Ratings by intuition were made on the scale of 1–8, with 8 being very in-tune. These boxplots contain the extreme of the lower whisker, the lower hinge, the median, the upper hinge, and the extreme of the upper whisker. The two hinges are the first and third quartile, and the whiskers extend to the most extreme data point which is no more than 1.5 times the interquartile range from the box.

FIG. 6.

Boxplots of acoustic measurements in singing of “Happy birthday” by 16 amusics and 16 controls: (A) pitch interval deviation (in semitones), (B) number of pitch interval errors (out of the total 23/24 intervals), (C) number of contour errors (out of the total 23/24 contours), and (D) number of time errors (out of the total 24/25 notes). The black dots denote individual participants in each group, with those at the same horizontal level having identical values. The data points that lie beyond the extremes of the whiskers are outliers, which are further denoted by small open circles.

FIG. 7.

Mean (and standard error) signed pitch interval deviations (in semitones) of amusics (grey dashed lines) and controls (black straight lines) against notated intervals (in semitones) in singing of “Happy birthday.”

FIG. 8.

Pitch direction identification thresholds (in semitones) of 15 amusics and 14 controls for (A) piano tones and (B) speech syllables.

FIG. 9.

Scatter plots of participants' scores across different tasks: (A) pitch thresholds (averaged across speech syllable and piano tone conditions; in semitones) against scores on the tone perception tasks (averaged across speech and non-speech conditions; in d′), (B) MBEA global scores (in percentage of correct responses out of the total 180 trials in the MBEA tasks) against scores on the tone perception tasks, (C) MBEA global scores against singing ratings (averaged across intuition and guideline conditions), and (D) tone production accuracy (rationalized arcsine transformed percent-correct scores) against scores on the tone perception tasks.