Sweetie Ears

Sweetie Ears research

Grounded in real research on early absolute pitch

Reference check verified through June 11, 2026

Sweetie Ears is built on the Eguchi chord-identification method — one of the few early-childhood approaches to absolute pitch with peer-reviewed longitudinal research behind it. Here is what that research shows.

~92%

of children — 22 of 24, ages 2–6 — acquired absolute pitch in a 2014 longitudinal study of the method.

Sakakibara 2014
3

peer-reviewed longitudinal reports document the method across 1999–2014.

2–6

the early-childhood age window research most associates with learning absolute pitch.

Every figure here is drawn from the peer-reviewed studies listed below.

Direct evidence for the Eguchi method

Longitudinal reports on the Chord Identification Method itself.

  1. Sakakibara, A. (1999). A Longitudinal Study of a Process for Acquiring Absolute Pitch. The Japanese Journal of Educational Psychology, 47(1), 19–27.

    https://doi.org/10.5926/jjep1953.47.1_19

  2. Sakakibara, A. (2004). Why Are People Able to Acquire Absolute Pitch Only During Early Childhood? The Japanese Journal of Educational Psychology, 52(4), 485–496.

    https://doi.org/10.5926/jjep1953.52.4_485

  3. Sakakibara, A. (2014). A longitudinal study of the process of acquiring absolute pitch: A practical report of training with the ‘chord identification method’. Psychology of Music, 42(1), 86–111.

    https://doi.org/10.1177/0305735612463948

Supporting evidence for key premises

Studies that support the premises CIM relies on, not the full program.

  1. Miyazaki, K., & Ogawa, Y. (2006). Learning Absolute Pitch by Children. Music Perception, 24(1), 63–78.

    https://doi.org/10.1525/mp.2006.24.1.63

  2. Crozier, J. B. (1997). Absolute Pitch: Practice Makes Perfect, the Earlier the Better. Psychology of Music, 25(2), 110–119.

    https://doi.org/10.1177/0305735697252002

  3. 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, 31(2), 155–171.

    https://doi.org/10.1177/0305735603031002292

  4. Saffran, J. R., & Griepentrog, G. J. (2001). Absolute pitch in infant auditory learning: Evidence for developmental reorganization. Developmental Psychology, 37(1), 74–85.

    https://doi.org/10.1037/0012-1649.37.1.74

  5. Saffran, J. R. (2003). Absolute pitch in infancy and adulthood: The role of tonal structure. Developmental Science, 6(1), 35–43.

    https://doi.org/10.1111/1467-7687.00250

  6. Takeuchi, A. H., & Hulse, S. H. (1993). Absolute pitch. Psychological Bulletin, 113(2), 345–361.

    https://doi.org/10.1037/0033-2909.113.2.345

  7. Levitin, D. J., & Rogers, S. E. (2005). Absolute pitch: Perception, coding, and controversies. Trends in Cognitive Sciences, 9(1), 26–33.

    https://doi.org/10.1016/j.tics.2004.11.007

  8. Zatorre, R. J. (2003). Absolute pitch: A model for understanding the influence of genes and development on neural and cognitive function. Nature Neuroscience, 6(7), 692–695.

    https://doi.org/10.1038/nn1085

  9. Gregersen, P. K., Kowalsky, E., Kohn, N., & Marvin, E. W. (2001). Early childhood music education and predisposition to absolute pitch: Teasing apart genes and environment. American Journal of Medical Genetics, 98(3), 280–282.

    https://doi.org/10.1002/1096-8628(20010122)98:3<280::AID-AJMG1083>3.0.CO;2-6

  10. Levitin, D. J., & Zatorre, R. J. (2003). On the nature of early music training and absolute pitch: A reply to Brown, Sachs, Cammuso, and Folstein. Music Perception, 21(1), 105–110.

    https://doi.org/10.1525/mp.2003.21.1.105

  11. 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, 21(1), 119–127.

    https://doi.org/10.1525/mp.2003.21.1.119

  12. Deutsch, D., Henthorn, T., Marvin, E., & Xu, H. (2006). Absolute pitch among American and Chinese conservatory students: Prevalence differences, and evidence for a speech-related critical period. The Journal of the Acoustical Society of America, 119(2), 719–722.

    https://doi.org/10.1121/1.2151799

  13. Gervain, J., Vines, B. W., Chen, L. M., Seo, R. J., Hensch, T. K., Werker, J. F., & Young, A. H. (2013). Valproate reopens critical-period learning of absolute pitch. Frontiers in Systems Neuroscience, 7, 102.

    https://doi.org/10.3389/fnsys.2013.00102

  14. Sakakibara, A. (1993). How Well Do Absolute Pitch Possessors Identify Tone Height and Tone Chroma. The Japanese Journal of Educational Psychology, 41(1), 85–92.

    https://doi.org/10.5926/jjep1953.41.1_85

  15. Sakakibara, A. (2011). Can Pitch Class Be Colored? The Proceedings of the Annual Convention of the Japanese Psychological Association, 75(0), 1AM100.

    https://doi.org/10.4992/pacjpa.75.0_1am100

The research on this page guides our design; individual outcomes vary and are not guaranteed.