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Noise in the head.

The eating of food is always associated with some sort of acoustic effects. There is always  slurping, chomping, gulping, chewing, sucking and crunching involved. In some cultures, such acoustic effects are supressed, whereas in others such noises are part of the customary order. 

The source of the sounds created during eating is, due to the nature of things, quite close to the hearing apparatus. Consequwntly the relatively weak 'noise in the head' is received quite loudly by the ear. 

Lately, psychologists have been interested in the loud, often ostentatiously loud, crunching of chips. Loud crunching of chips can be seen as an indication of their quality, and loud crunching at a party or a match is a symbol of machoness. And here we have an overlap of psychology with the physiology of crunching. It turns out that the crunching of chips creates a 'noise in the head' of arounf 100dB. But this is only half of the matter. 
Medicine states that noise of an intensity greater than 65dB creates a 40% increase in hypertension and psychological disturbances, especially in children. At a level of 51dB, one feels general unease. The greater the intensity of noise, the more serious the psychological consequences. Studies carried out on a group of students showed, that listening to noise raises the aggression levels of listeners. After the noise was stopped, the aggression did not immediatelely dissipate, rather lasted much longer than the noise. 

Below are listed some sources of noise and how we are affected by them : 


A quiet room 50-60
Washing machine 65
TV at about 3 m 68
Road traffic noise 75-85
Electric shaver 85
Electric chainsaw 100
Air raid alarm 130
Airplane at takeoff 120-140

[dB is a logarythmic scale and means that a difference of ten units corresponds to the intensity being ten times greater, three units means that the intensity is twice as much. Of course all of this depends on the location of the ear with respect to the source of noise, and the table gives the figures in terms of most common situations - this explains the relatively high values given for the electric shaver]. 
Taking into account the previously discussed connection between loud music and drug use, the matter takes on an even more serious tone. 




(C) (selected from publications of 
 R. Antoszewski

Titirangi, Auckland, 
New Zeland

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February  2003