Author(s): Madison M. Ward, Adam Jones
Mentor(s): Lynn H. White
Institution SUU
Live sound is referred to as analog. Recorded sound can be either digital or analog. The sounds we hear over digital devices start off as analog sound (i.e. live sound), get converted into binary code, and are then reconverted back to analog so that the brain can process them. Though the sound waves themselves are not digital, they are nevertheless referred to as “digital sound waves”. Analog recordings played back on an analog device (e.g. vinyl record player, cassette tape player) retain their analog format from the time the sound is recorded through until the time it is heard. The sound waves generated by these three sources (live, analog recordings, digital recordings) are not all the same. Live and analog recordings produce sound waves that are continuous and sinusoidal whereas digital sound waves are discrete and square. To date, our lab is the first to investigate whether analog and digital recordings impact the autonomic nervous system differently. Using a Biopac MP36 system, we recorded skin conductance (SC), heart rate (HR), and heart rate variability (HRV) as participants listened to the song Lean on Me twice: once on cassette tape (analog) and once as an mp3 (digital). Following a 5-minute baseline, the two formats of the song were played, counterbalanced for order and with a 5-minute rest (i.e. a second baseline) in between. We found significant differences between the two types of recordings relative to their respective baselines. Analog sound decreased SC whereas digital sound had no effect. This effect was observed in males only. Analog sound had no effect on HR, whereas digital sound increased it. This effect was observed in females only. While both analog and digital sound increased HRV, analog sound increased it more. This effect was observed in both males and females. We speculate that the observed sex disparities may be the result of the prosocial lyrics moderating the effect of sound differently for males and females. Regardless, the SC and HR data suggest that digital sound produced greater sympathetic nervous system activation indicative of a stress response. To the extent that HRV is believed to reflect general wellbeing, analog sound may be more conducive to wellness than digital sound. The possibility that digital sound may increase stress and detract from wellbeing has profound and worldwide implications, as we live in a digital era.