In previous investigation, we confirmed that jet noise depressed the physical growth of the school children living near the airfield.From these results it could be expected that the noisy environment might influence the reaction time, too.
In 1966, we investigated the phonating reaction time to tone click in the school children living around the Atsugi jet airfield.They were the same subjects as those examined in our previous investigation.We studied mainly the relationship between the reaction time and the distance from the airfield to the living region and also intended to analyze differences in human adaptabilities to the noisy environment according to sex and the growing process.
The results obtained are summerized as follows:
1.The developmental change of the reaction time.
The frequency histograms of the reaction time in the lower grade were characterized by delayed, low plateau (infantile pattern).The histograms became faster and more convergent within shorter range as the school grade advanced (grown-up pattern).
2.The relationship between the reaction time and the distance from the airfield to the living region of the school children.
(1) The reaction time in the children of the 6th grade in Y primary school, living farther from the airfield, did not show the difference of the histogram being caused by the living regions and all showed grown-up pattern.
(2) In S primary school children of the 6th grade (who lived nearer to the airfield than Y children), the reaction time of those living nearest appeared more strongly infantile than that of those living a little farther from the airfield.
This tendency was more remarkable in males.
(3) From the comparison between S and Y school children of the 6th grade, it could be seen that the reaction time of S had the stronger infantile tendency than that of Y children.
This tendency was more remarkable in females.
(4) From the results of (2) and (3), we observed the obvious difference of the reaction time between Y school children and those living nearest to the airfield in S school children.
Between the children examined, there were no essential differences in living conditions of them and their families which could possibly affect the reaction time.Thus, we concluded that such results as mentioned above were caused by jet engine noise which depressed the normal devel-opment of the reaction.
3.The difference of adaptabilities to the noisy environment according to sex and the growing process was not clearly observed in the present investigation.