The relation of simple response time to brain-wave frequency and the effects of age

Abstract

An experiment was performed to verify a previous finding of a positive correlation (0.81) between response time and period of the EEG. Details of this relationship, with reference to age and to a hypothesis concerning the function of the brain-wave cycle in simple behavior, were investigated. Reaction times and average period of the EEG, recorded in the interval of time between stimulus and response, were determined for 100 subjects ranging in age from 28–99 years. The major results were: 1. 1. The previous finding was confirmed. In the present study a correlation coefficient of 0.72 was obtained between average reaction time and the average period of the EEG. 2. 2. Excluding age from this relationship through the use of partial correlation, scarcely altered this coefficient. Age as a factor in the observed correlation was, therefore, ruled out. 3. 3. A highly significant positive correlation was obtained between age of the subjects and the average period of their brain waves. 4. 4. A low but statistically significant positive correlation was found relating average reaction time and age. This positive coefficient vanished and became negative when brain-wave period was “partialled out”. It was inferred, therefore, that EEG frequency is the central nervous system factor behind age-associated slowing in response time. 5. 5. Evidence derived from data of each subject taken singly showed the presence of a positive correlation between brain-wave period and reaction time in individual subjects. 6. 6. Taken as a whole, the data support the hypothesis that the brain-wave cycle is the basic unit of time in terms of which a response is programmed by the central nervous system.