Associations Between Resting Respiratory Sinus Arrhythmia, Intraindividual Reaction Time Variability, and Trait Positive Affect
Resting respiratory sinus arrhythmia (RSA) reflects vagal tone, which has been found to be related to trait positive affect (PA). Resting RSA has also been found to be related to intraindividual reaction time (RT) variability (IIV), which is an index of executive brain function. However, research has yet to investigate whether IIV is associated with trait PA, and whether IIV interacts with resting RSA to predict trait PA. To examine this issue, data of trait PA, 5-min resting RSA, and trial-to-trial IIV of a flanker task (target detection) were collected in 117 young healthy adults. Results showed that IIV under congruent, incongruent, and combined conditions obtained in the flanker task was associated with resting RSA and trait PA. Resting RSA interacted with IIV under incongruent conditions to predict trait PA, such that resting RSA positively predicted trait PA in high IIV under incongruent conditions, but not in low IIV under incongruent conditions. These findings suggest that executive brain function indexed by IIV might be a central nervous correlate of trait PA, and the executive brain function indexed by IIV under incongruent conditions and the vagal tone indexed by resting RSA interactively predict trait PA, might have health implications.