Cardiac-somatic changes during a simple reaction time task: A developmental study

The relationship during a simple reaction time task between heart rate and four measures of task irrelevant somatic activity was evaluated in four age groups of children, i.e., 4-, 5-, 8-, and 10-year-olds and young adults, in order to evaluate further a hypothesized coupling of cardiac and somatic activity. At all age levels, phasic decreases in both heart rate and somatic activity coincident with performance were found with the magnitude of the effect increasing with age only on three somatic measures. However, tonic levels of both heart rate and somatic activity decreased with age. Performance on the reaction task was found to be inversely related to the age-related phasic somatic effects as well as age-related tonic heart rate and somatic activity.