We present the construction and analysis of a dynamical system model for human decision making in sequential two-choice tasks, in which a human subject makes a series of interrelated decisions between two choices in order to obtain the maximum reward. For a nominal decision making policy inspired by behavioral aspects of humans, we show asymptotic behavior of such decision making process in sequential two-choice tasks for various types of reward structures. Our work gives a control theory oriented perspective to the experiments carried out by cognitive scientists.