Factors Affecting Reaction-Time Testing and the Interpretation of Results

Abstract

The aim of this study was to identify factors that might affect reaction-time (RT) testing and interpretation. Simple reaction time and choice reaction time were measured in a cohort of 893 white young men. Age, body size, color vision, and intelligence (IQ) were analyzed as subject-related factors. Effects of time of day of test and different examiners were analyzed in relation to testing facilities. All factors were statistically correlated to RTs; however, the relationships between age and RTs and between height and RTs were noticeably weak and apparently insignificant in practice. A defect in color vision was notably associated with slow choice RT and with mistakes on the test. As the choice was coded by color in the choice RT test, the result was expected. Low IQs were significantly related with slow RTs. Slow RTs have been correlated with low-grade IQs in previous studies also. Lower grades and greater variation in RTs were recorded just before meals or if testing was done outside the daily testing schedule. The examiner supervising the RT testing significantly affected the results. It was concluded that the introduction for tests should be given impersonally using a tape recorder or comparable equipment.