The effect of environmental factors on job Performance using manual and mental tests

Introduction: Individuals' jobs performance is one the most important factors in industries and organizations. The aim of the present study was to investigate the simultaneous effect of exposure to noise, lighting and heat stress on the workers' job performance. Material and Method: In this analytical-descriptive study, 30 employees of the auto parts manufacturer, in Tehran city, were chosen by simple random sampling. By controlling and limiting confounding factors, the simultaneous effect of noise, lighting and heat stress on the participants' job performance was investigated, using tow series of mental and manual testes. Data were analyzed by SPSS software version 18, using descriptive statistic, ANOVA and Tukey testes and also person correlation coefficient. Result: The results showed that by increasing the noise and heat stress (P = 0.046, r=0.344) and decreasing of lighting (P =0.008, r = -0.472), the required time for performing the Minnesota placement test has been gone up. Moreover, the result revealed that by increase in noise and heat stress = 0.007, r = 0.478) and decrease in lighting (P=0.003, r = 0.523) the required time for competing hand tool dexterity test has been also increased at surface and mid level. Conclusion: Finding of the present research manifested that increase in noise and heat stress and also reduction in lighting lessen the speed of manual tests and time and accuracy of mathematical calculations. Therefore this result confirm the effects of various environmental factors on individuals' job performance, in a way that by variation of different environmental factors, time of manual test and time and accuracy of mental tests would be changed.