T HE A CTUAL VS .P REDICTED E FFECTS OF I NTONATION A CCURACY ON V OCAL P ERFORMANCE Q UALITY R ICHARD A. WARREN &MEAGAN E. C URTIS Purchase College, State University of New York THE BELIEF THAT INTONATION ACCURACY IS A KEY determinant of musical performance quality is ubiqui- tous in music pedagogy; nonetheless, empirical valida- tion of this belief is lacking. We investigated the effects of intonation accuracy on perceived performance qual- ity and assessed whether music professionals’ beliefs about the importance of intonation are consistent with these effects. In Experiments 1 and 2, participants lis- tened to vocal performances that were in tune, moder- ately out of tune, or severely out of tune. Only severe mistunings caused decreases in performance quality rat- ings for intonation insensitive listeners (those who per- formed poorly on a mistuning detection prescreening). However, both moderate and severe mistunings were detrimental to the ratings of intonation sensitive listen- ers. These results indicate that moderate mistunings exert a negative influence on the perceived quality of a performance only if the listener can explicitly detect the mistunings. If a listener cannot explicitly detect the mistunings, those mistunings do not implicitly exert a negative influence on the perception of the perfor- mance. In Experiment 3, music professionals heard samples of performances from Experiments 1 and 2 in each intonation condition and were asked to estimate the impact of the mistunings on listeners’ ratings of performance quality. Their predictions were compared to the actual performance quality ratings obtained in Experiment 2. Music professionals overestimated the impact of moderate mistunings for both intonation sen- sitive and insensitive listeners, suggesting that music pro- fessionals may hold inaccurate beliefs about the importance of intonation accuracy in vocal performance. Received: February 4, 2014, accepted September 28, 2014. Key words: intonation, music perception, performance quality, singing, vibrato R ESEARCH ON THE DETERMINANTS OF MUSICAL performance quality has been scarce, a phenom- enon that may reflect a tacit belief that per- formance quality is largely influenced by elusive factors beyond the scope of scientific investigation. This intu- ition is corroborated by research in which trained lis- teners seem unable to discriminate between the quality of various performance components (Thompson & Williamson, 2003) as well as between timbral quality and intonation accuracy (Madsen & Geringer, 1981). Such ambiguity might be expected, as the perception of performance quality is likely influenced by a host of factors exogenous to the performance itself, such as listener characteristics, cultural context, and musical genre. Nonetheless, understanding the determinants of performance quality is crucial to the extent that musicians aim to maximize the quality of their music. Although many professionals have strong convictions regarding the importance of various performance char- acteristics, these convictions are rarely held to empiri- cal scrutiny. Although many performance attributes may be diffi- cult to study experimentally, a small number of measure- able and manipulable attributes may have predictable and meaningful influences on quality. Intonation is a likely candidate for such an attribute. The heavy empha- sis on intonation in musical performance and pedagogy suggests that it may be a crucial determinant of quality. Furthermore, the emergence of pitch editing software allows for the quantification and manipulation of into- nation with relative ease. Despite the promise of this line of investigation, the relationship between intonation accuracy and performance quality has received little empirical attention. The accuracy of intonation is determined by culturally specific tuning systems. In Western music, fixed-pitch instruments are generally tuned to the equal tempered tuning system. Under this system, the octave (two tones separated in fundamental frequency by a ratio of 2:1) is divided into 12 logarithmically equal pitch classes. The distance between any two adjacent pitch classes is per- ceptually equal and measured in a unit called a semitone. This tuning system is usually set relative to the pitch class A tuned to 440 Hz. Thus, each pitch class under this tuning system has a ‘‘correct’’ fundamental fre- quency tuning value relative to this standard. Devia- tions in intonation from this standard are referred to as flat or sharp—below or above the target fundamental Music Perception, VOLUME 33, ISSUE 2, PP. 135–146, ISSN 0730-7829, ELECTRONIC ISSN 1533-8312.  2015 BY THE REGENTS OF THE UNIVERSITY OF CALIFORNIA ALL RIGHTS RESERVED. PLEASE DIRECT ALL REQUESTS FOR PERMISSION TO PHOTOCOPY OR REPRODUCE ARTICLE CONTENT THROUGH THE UNIVERSITY OF CALIFORNIA PRESS ’ S REPRINTS AND PERMISSIONS WEB PAGE, HTTP:// WWW. UCPRESS . EDU/ JOURNALS . PHP? P¼REPRINTS . DOI: 10.1525/ MP.2015.33.2.135 Intonation Accuracy and Performance Quality 135