By Eleanor Hutcheon
Absolute pitch (AP), also known as “perfect pitch”, is defined as the ability to name or produce a note of a particular pitch in the absence of a reference note (Deutsch, 2013). It is a rare ability, with an estimated occurrence of 1 in 10,000 people, that requires the capacity to mentally classify sounds into memorable categories (Takeuchi & Hulse, 1993). By contrast, relative pitch is a skill shared by most musicians and requires a starting note as an anchor point whereby other intervals can be identified. Comparable to how the general population would be able to identify an object of a particular colour, this task is simple and immediate to the small percentage of the population who possess AP. The ability is deemed to neither be completely inherited nor teachable (Chin, 2003), and attempts to train adult musicians in AP have yielded largely unsuccessful results (Rakowski & Miyazaki, 2007). It is instead thought to rely upon musical exposure during a critical period of development (Russo, et al., 2003). How this very specific talent is reflected in brain networks is not well understood. Previous attempts to classify AP stereotyped connectivity have yielded highly heterogeneous findings with inconsistencies arising in the location and direction of brain connectivity, whether a deficit or excess is present in the former, latter, or both.
A new study, published in January 2021 to the Journal of Neuroscience, suggests that regardless of innate pitch ability, musical training is associated with robust changes in large-scale brain networks. Researchers collaborating between Stanford University and the University of Zurich undertook the largest comprehensive assessment to date, studying the effects of musicianship and absolute pitch on intrinsic functional and structural brain connectivity (Leipold, et al., 2021). Using resting-state functional magnetic resonance imaging (rsfMRI) and diffusion-weighted imaging (DWI), the brains of 52 AP, 51 non-AP musicians, and 50 non-musicians were analysed. rsfMRI employs a measure of blood oxygenation to quantify neuronal activity whereas DWI uses water diffusion to investigate the connection probability of white-matter tracts between brain areas. Maps of the participants’ brains neural functional connectivity were then compared to assess the effect of musicianship and absolute pitch. Global differences in synchrony of brain activity were characterised in addition to those relating to connections between specific areas associated with music processing such as the primary auditory area and frontal cortices.
Remarkable similarity was found between the brain networks of the two musician groups; however, both were shown to have stronger white matter connections between auditory associated areas and those relating to higher level processing than the non-musician participants. Earlier age of musical training onset was found to be associated with stronger structural connections. This indicates how experience shapes the brain, particularly in early life, and the physical imprint musical expertise can leave on our neural connections. It is important to note however, that these measures were not associated with cumulative training hours once musical training was instigated suggesting a sensitive period in early life when the potential for plasticity is particularly high allowing microstructural changes to occur. The effects of musicianship were also found to be stronger for functional measures of connectivity (rsfMRI) compared to the structural measures (DWI).
The researchers stated that the results “should not be regarded as evidence that there are no effects of AP on the brain in general”. The effects of AP on large-scale brain networks were posited to be subtle and may require task-based experiments investigating tone labelling in action or larger cohort sizes to be uncovered. Future studies could benefit from a hypothesis-driven framework, perhaps through closer investigation of brain regions involved in music production and the playing of instruments.
Chin, C. S., 2003. The Development of Absolute Pitch: A Theory Concerning the Roles of Music Training at an Early Developmental Age and Individual Cognitive Style. Psychology of Music, 4, 31(2), pp. 155-171.
Deutsch, D., 2013. Absolute Pitch. The Psychology of Music, pp. 141-182.
Leipold, S., Klein, C. & Jäncke, L., 2021. Musical expertise shapes functional and structural brain networks independent of absolute pitch ability. The Journal of Neuroscience, 1.pp. JN-RM-1985-20.
Rakowski, A. & Miyazaki, i., 2007. ABSOLUTE PITCH: COMMON TRAITS IN MUSIC AND LANGUAGE, s.l.: s.n.
RUSSO, F. A., WINDELL, D. L. & CUDDY, L. L., 2003. Learning the ““Special Note””: Evidence for a Critical Period for Absolute Pitch Acquisition. Music Perception, 9, 21(1), pp. 119-127.
Takeuchi, A. H. & Hulse, S. H., 1993. Absolute pitch. Psychological Bulletin, 113(2), pp. 345-361.