We addresses the longstanding issue of the Speed-Accuracy Tradeoff (SAT) in decision-making processes by introducing an alternative theoretical framework. Traditional models, such as the Diffusion Decision Model (DDM), have often relied on manipulating the decision threshold to explain SAT, but inconsistent findings have prompted a reevaluation. Pitfalls in previous research highlight the need for alternative approaches. This paper explores the Ornstein–Uhlenbeck Model (OUM), which introduces a unique self-excitation parameter influencing the drift rate, offering a novel perspective on SAT. Unlike DDM, OUM maintains a fixed boundary separation parameter across conditions, emphasizing the role of self-excitation in shaping decision dynamics. The article compares DDM and OUM using various datasets, conducts model comparisons, and employs cross-fitting methods to explore their relationships and parameter identifiability. By proposing a new theoretical model and systematically examining its performance, this paper contributes to the ongoing discourse on the mechanisms underlying SAT in decision-making processes.