The effect of sound with different frequencies on selective attention and human response time

Sound is one of the most effective exogenous factors affecting brain processing mechanisms, including attention that affecting human error and occupational accidents. The purpose of this study was to investigate the effect of sound frequency on noise annoiance, selective attention and human response time. This research is an interventional study that was conducted in 2017 on 60 students of Gonabad University of Medical Sciences. Measurements and tests were performed at two positions of before and during exposure to noise at various frequencies of 500, 1000, 2000, 4000 and 8000 Hz. To determine the sound with different frequencies, noise.exe software was used and to determine the accuracy of the intensity and frequency of sound, the TES 1358 TES sounding device was used. In the next step, cognitive performance tests including reaction time, accuracy and attention were measured by the test Stroop Complex. Data analysis was performed using spss. The mean age of males was 21.12 with a standard deviation of 0.13 and the mean age of females was 19.19 years with a standard deviation of 0.5. The highest degree of noise is at a frequency of 4000 and 8000 Hz The results of ANOVA showed that there is a significant relationship between noise anniance with different frequencies. By increasing the frequency from 500 to 4000 Hz, the reaction time is reduced and from 4000 to 8000 Hz, the reaction time increases. There is no meaningful relationship between the reaction time and the various frequencies.in both male and female groups, exposure to sound at all frequencies increases the number of errors and the highest error rate is at 1000 Hz, there is a significant difference between the interference score and the interference time with different frequencies. Due to the significance relationship between frequency of sound and interference score and interference time of individuals, by changing these factors, the reaction time and the time for mental tests and the degree of error of individuals are changed. In job posts and sensitive occupational tasks requiring the use of cognitive functions such as precision and reaction time the frequency of the sound should be considered