Blinks & Hisses

All that man knows about the outside world he learns through his senses. But these "physical systems" are as imperfect as man-made instruments: they have their failings and foibles, too.

The Deceptive Ear. In the current Journal of the Acoustical Society of America, Dr. James P. Egan of the University of Wisconsin describes what happens when different sounds enter left & right ears. He put headsets on eight "naive subjects" (not aware of the purpose of the experiment). Through one earphone came a recorded voice. Through the other came a sound like the hiss of steam. When the hiss was moderately loud, it made the speech sound louder, "as if the talker raises his voice in order to make himself heard above the noise."

The Inconstant Eye. In Britain's Nature magazine, Dr. Robert W. Lawson of the University of Sheffield considers the human blink. For the average (J-type) eye, says Dr. Lawson, blinks last about .3 seconds and come about 2.8 seconds apart.

Dr. Lawson figured that J-type people are visually "blacked out" during 11% of the time they think their eyes are open. He believes that blinking is responsible for many a misread scientific instrument, many a missed tennis ball, many an auto accident.

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