Perceiving Music Through the Lens of Synaesthesia and Absolute Pitch

Synaesthesia and absolute pitch (AP) are two rare conditions that occur more frequently within populations of artistic professionals. Current thinking surrounding synaesthesia and AP and their relationship to music perception form the focus of this article. Given that synaesthesia has rarely been discussed in the music literature, the article surveys and consolidates general neurobiological, psychological, and behavioural evidence to summarise what is currently known on this topic, in order to link this back to the conditions that most relate to music. In contrast, research on AP is now well established in the music literature, but the important gap of linking AP to other conditions such as synaesthesia has yet to be fully explored. This article investigates the potential relationship between synaesthesia and AP for musicians who possess both conditions by systematically comparing the definitions, classifications, prevalence, diagnoses, and impacts on music perception of synaesthesia and AP and provides insights into the varying states of the literature and knowledge of both conditions. In so doing, this article aims to facilitate a greater understanding of music and auditory forms of synaesthesia and their interaction with AP and encourage increased research effort on this important topic.

Song imitation in congenital amusia: Performance partially facilitated by melody familiarity but not by phonetic content

Congenital amusia is a neurogenetic disorder of pitch perception that may also compromise pitch production. We explored whether vocal imitation of song in amusia is influenced by melody familiarity and phonetic content. Thirteen Mandarin-speaking amusics and 13 matched controls imitated novel song segments with lyrics and on the syllable /la/ while their output was recorded. Eleven out of these participants in each group also imitated segments of a familiar song. Subsequent acoustic analysis was conducted to measure pitch and timing matching accuracy. While amusics’ performance was facilitated by melody familiarity in terms of pitch interval deviation, signed interval deviation and number of contour errors, they showed compromised performance compared to controls in absolute pitch deviation, number of pitch interval errors, duration difference, interonset interval difference, and number of time errors in both familiar and novel song conditions. The presence of lyrics did not affect either group’s performance substantially. While a stronger relationship between music perception and novel melody imitation was observed in amusics as opposed to familiar melody imitation, controls showed the opposite pattern. We discuss the implications of the study in terms of music familiarity, memory demands, the relevance of lexical information and the link between perception and production.

Learning the Special Note: Evidence for a critical period for absolute pitch acquisition

Children (3–6 years old) and adults were trained for 6 weeks to identify a single tone, C5. Test sessions, held at the end of each week, had participants identify C5 within a set of seven alternative tones. By the third week of training, identification accuracy of children 5–6 years old surpassed the accuracies of children 3–4 years old and adults. Combined with an analysis of perceptual strategies, the data provide strong support for a critical period for absolute pitch acquisition.

Learning the Special Note: Evidence for a critical period for absolute pitch acquisition

Children (3–6 years old) and adults were trained for 6 weeks to identify a single tone, C5. Test sessions, held at the end of each week, had participants identify C5 within a set of seven alternative tones. By the third week of training, identification accuracy of children 5–6 years old surpassed the accuracies of children 3–4 years old and adults. Combined with an analysis of perceptual strategies, the data provide strong support for a critical period for absolute pitch acquisition.

Change detection of auditory tonal patterns defined by absolute versus relative pitch information. A combined behavioural and EEG study

The human auditory system often relies on relative pitch information to extract and identify auditory objects; such as when the same melody is played in different keys. The current study investigated the mental chronometry underlying the active discrimination of unfamiliar melodic six-tone patterns by measuring behavioural performance and event-related potentials (ERPs). In a roving standard paradigm, such patterns were either repeated identically within a stimulus train, carrying absolute frequency information about the pattern, or shifted in pitch (transposed) between repetitions, so only relative pitch information was available to extract the pattern identity. Results showed that participants were able to use relative pitch to detect when a new melodic pattern occurred. Though in the absence of absolute pitch sensitivity significantly decreased and behavioural reaction time to pattern changes increased. Mismatch-Negativity (MMN), an ERP indicator of auditory deviance detection, was elicited at approximately 206 ms after stimulus onset at frontocentral electrodes, even when only relative pitch was available to inform pattern discrimination. A P3a was elicited in both conditions, comparable in amplitude and latency. Increased latencies but no differences in amplitudes of N2b, and P3b suggest that processing at higher levels is affected when, in the absence of absolute pitch cues, relative pitch has to be extracted to inform pattern discrimination. Interestingly, the response delay of approximately 70 ms on the behavioural level, already fully manifests at the level of N2b. This is in accordance with recent findings on implicit auditory learning processes and suggests that in the absence of absolute pitch cues a slowing of target selection rather than a slowing of the auditory pattern change detection process causes the deterioration in behavioural performance.

A new approach to measuring absolute pitch on a psychometric theory of isolated pitch perception: Is it disentangling specific groups or capturing a continuous ability?

Absolute Pitch (AP) is commonly defined as a rare ability that allows an individual to identify any pitch by name. Most researchers use classificatory tests for AP which tracks the number of isolated correct answers. However, each researcher chooses their own procedure for what should be considered correct or incorrect in measuring this ability. Consequently, it is impossible to evaluate comparatively how the stimuli and criteria classify individuals in the same way. We thus adopted a psychometric perspective, approaching AP as a latent trait. Via the Latent Variable Model, we evaluated the consistency and validity for a measure to test for AP ability. A total of 783 undergraduate music students participated in the test. The test battery comprised 10 isolated pitches. All collected data were analyzed with two different rating criteria (perfect and imperfect) under three Latent Variable Model approaches: continuous (Item Response Theory with two and three parameters), categorical (Latent Class Analysis), and the Hybrid model. According to model fit information indices, the perfect approach (only exact pitch responses as correct) measurement model had a better fit under the trait (continuous) specification. This contradicts the usual assumption of a division between AP and non-AP possessors. Alternatively, the categorical solution for the two classes demonstrated the best solution for the imperfect approach (exact pitch responses and semitone deviations considered as correct).