Author(s): Damian V. Jesus, Jordanelle A. Caldwell, Sam Webster, Alexis Downey, Mason Huff, Paige Kennedy, Pengcheng Li, Kaden Gardner
Mentor(s): Lynn H. White
Institution SUU
Live sound and sound played from a vinyl record or cassette tape are called analog. They take the form of a continuous sinusoidal wave. Most recorded sounds we hear today are analog sounds converted to a binary code. This code, often saved as mp3 or wav files, is then reconverted back to analog by the player device so that it can be processed by the brain. This converted analog sound wave (hereafter referred to as digital sound) differs from its original analog form. It is now a discrete square wave. But for our lab, no one has investigated whether analog and digital sound waves have different effects on brain and behavior. In our experiment, 20 females listened to the song Lean on Me twice: once on cassette and once as an mp3. The conditions were counterbalanced for order with a 5-minute rest in between. While listening, we recorded EEG from a 32-channel system. Pre-processed EEG signals were converted using a Fast Fourier Transformation. Average power was exported, and asymmetry scores calculated for 14 right-left hemispheric pairs for the middle 180 seconds of the song’s duration. For alpha frequencies, digital sound produced asymmetry in the right frontal, temporal, and parietal regions. Analog sound produced asymmetry in the right frontal pole, and to a lesser extent, in the right frontal region. Although both digital and analog sound produced right frontal asymmetry, the effect was stronger for digital sound. We also found preliminary evidence that the effect of analog sound fades over time, while the effect of digital sound increases over time. For beta frequencies, digital sound produced asymmetry in two frontal regions, and across the mean of several frontal and central regions. Analog sound produced no asymmetry except for a 30 second interval in the middle of the 180 second time period we analyzed. This effect of analog sound disappeared when the full 180 seconds was considered. Though we did not take any behavioral or attitudinal measures, our EEG findings for the effect of digital sound align with other researchers’ investigation of EEG showing that 1. as right frontal asymmetry increases for alpha, state empathy decreases, and 2. as right frontal asymmetry increases for beta, trait aggression increases. We are currently investigating the effect of analog and digital sound on EEG, mood, state empathy, and state aggression. Should our results confirm these associations, the implications would be profound and worldwide.