This article considers a signal detection theory (SDT) approach to evaluation of performance on the Montreal Battery of Evaluation of Amusia (MBEA). One hundred fifty-five individuals completed the original binary response version of the MBEA ( n = 62) or a confidence rating version (MBEA-C; n = 93). Confidence ratings afforded construction of empirical receiver operator characteristic (ROC) curves and derivation of bias-free performance measures against which we compared the standard performance metric, proportion correct (PC), and an alternative signal detection metric, d ′ . Across the board, PC was tainted by response bias and underestimated performance as indexed by A z , a nonparametric ROC-based performance measure. Signal detection analyses further revealed that some individuals performing worse than the standard PC-based cutoff for amusia diagnosis showed large response biases. Given that PC is contaminated by response bias, this suggests the possibility that categorizing individuals as having amusia or not, using a PC-based cutoff, may inadvertently misclassify some individuals with normal perceptual sensitivity as amusic simply because they have large response biases. In line with this possibility, a comparison of amusia classification using d ′ - and PC-based cutoffs showed potential misclassification of 33% of the examined cases.
two experiments examined effects of regulatory fit and music training on performance on one subtest of the Montreal Battery of Evaluation of Amusia (MBEA). Participants made same-different judgments about melody pairs, while either gaining points for correct answers (gains condition) or losing points for incorrect answers (losses condition). In Experiment 1, participants were told that the test was diagnostic of their music ability and then were asked to self-identify as a musician or a nonmusician. In Experiment 2, participants were given either a promotion-focus prime (a performance-based opportunity to gain entry into a raffle) or a prevention-focus prime (a raffle ticket was awarded at the start of the experiment and participants prevented its loss by maintaining a certain level of performance). Consistent with a regulatory fit hypothesis, nonmusicians and promotion-primed participants performed better in the gains condition than the losses condition, while musicians and prevention-primed participants performed better in the losses condition than the gains condition. Experiment 2 additionally revealed that regulatory fit effects were stronger for musicians than nonmusicians. This study demonstrates that regulatory fit impacts performance on the MBEA and highlights the importance of motivational orientation with respect to musician performance advantages in music perception.
CONGENITAL AMUSIA, OR 'TONE DEAFNESS,' IS A LIFELONG impairment in musical ability, reported to be present in approximately 4% of the general population.We examined the meaningfulness of 4% as an estimate of the prevalence of amusia given current test-based methods; here we focused on the Distorted Tunes Test (DTT) and the Montreal Battery of Evaluation of Amusia (MBEA). We demonstrate that estimates of prevalence critically depend on the specific cutoff applied to the test and the degree of skew in the distribution of scores. Broader consideration of this issue reveals that the use of arbitrary cutoffs is not unique to diagnosis of congenital amusia. We conclude that although the MBEA has shown to be a valuable diagnostic tool, caution is warranted against attributing meaning to the reported 4% rate of congenital amusia that is so widely cited in the literature.