Shervin Riahi 11/16/00

NPSYCH 12a Professor Sekuler

Sensory Deprivation Experiment

I performed my 8 hours of partial hearing loss from 1PM-9PM on Wednesday,

November 15. As soon as I plugged up my ears, the first thing that struck me was an increased sensation of pressure around my head, as if I had caught a cold. I suddenly became much more conscious of whenever I would swallow or sniffle, since the sounds associated with those events were much more pronounced, and I also could hear the occasional heartbeat. Walking around produced a horribly jarring sound in my head, which, although at first was uncomfortable, I quickly grew used to, and coughs and sneezes, louder sounds which originate from inside my body, sounded lower and more guttural than usual. The altered perception of these sounds can be accounted for in two ways: the ear plugs are blocking out certain frequencies that I am accustomed to hearing with some of those events, and much of what I do hear is due to bone conduction, especially whenever I spoke or swallowed. The "sickly" feeling is most probably due to the increased pressure on the ear drum created by the ear plug. Since this pressure was over a localized region, and therefore there was no way to equalize it through my middle ear, I presume that is why the simple act of swallowing or holding my nose and attempting to breath through it was of no avail.

When I tried using my computer, I immediately noticed that I couldn’t hear any mouse clicks, which, surprisingly enough, made it very awkward for me to use the mouse since I am so used to associating the click of the mouse to the actions onscreen. Curiosity prompted me to try to play a game that heavily relied on sound to direct the player, and even though it only felt as if the speaker volume had been turned down, I quickly gave up since it felt rather weird playing with such an auditory condition. Similarly, listening to music was a bit disturbing; songs that I was so accustomed to hearing "normally" now sounded dampened and certain instruments sounded unusual within the songs. Taking a cue from this, I wondered how different the experience of playing an instrument would be, so I played the piano for a little while. The lack of any background sounds created a nice medium in which to play (no distracting background sounds, for the most part), but I quickly became conscious of a new noise, particularly after playing for an extended period of time: it’s indescribable, somewhat similar to the sound a jet makes when passing high above in the stratosphere, or a muffled in-sink garbage disposal. Overall, the notes didn’t sound too different from usual, apart from the obvious dampened sound, although the notes two octaves above middle C were rather hard to hear. I can’t come up with a satisfying explanation for the extra noise I was hearing; perhaps it was an echo that emanated from the body of the piano, a sound that is usually masked by the notes. Looking at the chart of frequencies vs. notes on a piano on page 349 of our book, the frequencies that were present spanned the range from 60 Hz to a little over 1,000 Hz. The graph on page 335 relating sound intensity to frequency can help shed light onto my perception of the sounds: judging by the magnitudes of attenuation of the particular frequencies induced by the ear plugs, the notes with frequencies higher than 800 Hz or so were attenuated by about 30 decibels, raising the audibility function curve by such an amount.

When I could finally remove the earplugs from my ears, I was immediately greeted by a rushing of blood back into my ears (felt akin to pins-and-needles) and a profound acuity to the sounds in my environment, although this only lasted for a few minutes. The fan of my computer, the clicks of the mouse button, the TV that apparently had been on upstairs (though I hadn’t a clue it was on before), and other ambient sound all struck me as being awfully loud.