We all know that humans are equipped with five basic senses: sight, taste, smell, hearing and touch. Amongst these, sight is the sense for detecting electromagnetic rays at the visual range. Taste and smell are chemical senses. Out of the five, hearing and touch are stimulations based on vibrations. As explained in the article ‘Touch Your Sound’, there were certain things that made me believe that touch may be an alternate sense for hearing. In fact, that was what hunched me to name the website ‘Touch Your Sound’, as we would be covering subjects relating to sound in an alternate angle.
Dr. Jeffrey M Yau on the 25th of May, 2011 had submitted his paper, at the 161st meeting of the Acoustical society of America on ‘Feeling with your ears and hearing with your hands’. Dr. Yau, currently a Post-doctoral Fellow at the John Hopkins University, is currently using trans-cranial direct current stimulation (TDCS) to investigate cross modal recruitment of visual and auditory cortex for tactile perception. Some of the publications by Dr. Yau are on Perception and Psychoacoustics, Journal of Neurophysiology, Current Biology and Communicative & Integrative Biology. He and his team had designed various experiments to test the interaction between the senses touch and hearing.
Listen to the interview with Jeffrey M Yau, in which he speaks about his paper. Click here for the Transcript of the interview.
Firstly, he and his team fed vibrations at particular frequencies onto the fingers of the participants to test the response from the sense of touch alone. The participants identified the frequencies fed into the fingers correctly. In the second stage, the participants were fed with audio at a particular frequency on a headphone along with the vibrations on their fingers. The observations they made were that when the frequency of the sound was increased, the participants tend to perceive that the vibrations fed on their fingers are of higher frequency than they really are. The participants only perceived a change in frequency domain when audio was played along with vibration. They did not feel any change in the intensity of vibration. In the second set of experiments, the same was repeated to find the effect of touch on sound. It was observed that the participant had a deviated perception of the sound when a certain frequency of vibration was applied. Dr. Yau says that, “this proves that audio-tactile relations in frequency domain are reciprocal”. In this case, interestingly “vibrations did bias the loudness of sounds”. This means that a sound seemed louder if certain vibration was felt which was not observed in the reverse scenario.
Dr. Yau suggests that this finding can be applied in various different ways. One application which he mentioned was for therapeutical practices such as stroke rehabs etc. Another one was for smartphones where different vibrations can be used for different indications. It was in fact, the final point of his paper that interested me the most which said that vibrations would affect the loudness of sounds. Nowadays, a big rumble in a cinema is created by pouring in a lot of bass sounds. I reckon it would be more realistic to feel the whole rumble on your feet as vibrations when the mighty ‘King Kong’ enters the big screen.
In a way, Dr. Yau’s paper goes along with the theme of the website. The title of his paper has proved that it is possible to feel with your ears and hear with your hands.