Sanskrit Chant Pilot Study

Tamil Nadu, 2018. X-System is designed to be a universal musical tool, capable of predicting neurophysiological responses to music in all cultures.

In this study, school children and staff from the Tamil Nadu region of South India, all with different levels of understanding of Sanskrit, were played Sanskrit chants with contrasting X-System predictions. X-System predicted changes in heart rate in the subjects with very high accuracy, suggesting that it is indeed a tool for predicting neurophysiological response to music that can work effectively in different musical cultures.

A repertoire of 30 Sanskrit chants was recorded by Arjta Chowdhury and Dr. Sampadananda Mishmra. Particular attention was paid to consistency of recording acoustics, distance from microphone, recording levels, sound treatments etc. These recordings were then analysed by X-System. A sequence of three chants was chosen on the basis of their contrasted character and distinctive X-System predictions – the first, with female voice, predicted to be relaxing in character; the second, with male voice, arousing and the third, once again with female voice, to be both relaxing and mildly stimulating.

Indravajra Shloka 1-12 repetitions; Indravajra Shjola 4-12 repetitions ; Bhujanga Prayaatam Shjloka 1-11 repetitions

A group of children n=20 was selected to include a spread of ability, gender and knowledge of Sanskrit. In addition, n=2 members of the school staff volunteered to be subjects. Each subject listened to the sequence of three chants for approximately 15 minutes, wearing the wrist sensor to record autonomic response (Heart Rate).

Four data points were selected and calculated:

  1. a baseline reading before the first chant recording was played
  2. the average of the mean heart rate across all subjects over the last 20 seconds of chant 1
  3. the average of the mean heart rate across all subjects over the last 20 seconds of chant 2
  4. the average of the mean heart rate across all subjects over the last 20 seconds of chant 3

The baseline value for the X-System plot was taken from the baseline sensor reading, then the predicted net arousal index was projected above the lowest arousal value of the heart rate data (60 beats per minute), X-System predicted the exact collective heart rate for data points one, two and three (i.e. 87, 84 and 86 beats per minute) and at data point 4 predicted 84.5 rather than 85, a 4% error, 1% overall. There was too little comparable data (multiple heart rate readings versus single X-System predictions) to calculate the Pearson Correlation Coefficient or other standard measures of correlation

X-System, which has a proven record of predicting changes in heart rate for Western music, predicted the outcome of this experiment among South Indian listeners, including precise heart rate levels, to high accuracy (99% overall).

The data did not achieve significance, probably because of the diversity of the population which included a wide range of standard deviation (a mean of 11.0161) and heart rate change clustered closely together (an average of 1.389% change).

Other Papers

1611 Summary of X-System Croydon Trial

Queen Mary University, Imperial College, The Royal College of Music 2017. The earliest known reference to entrainment is Christiaan Huygens’ description of two pendulum clocks ‘‘falling into synchrony’’.

HRV Paper

Northumbria University, 2019. Heart Rate Variability (HRV) is a useful measure of valence in music, that is to say how positive or negative the emotions of the listener are.

IEEE Paper, September 2020

Northumbria University/NHS TEWV. Early in the COVID-19 pandemic, X-System was invited to create playlists for the NHS Recovery College Online website.

Predictions of Arousal and Violence Paper, Spring 2019

Tamil Nadu, 2019. In this study, validation of X-System valence predictions was carried out in an RCT, once again, in a non-Western culture.