Catecholamines play a crucial role in updating mental representations in a world where constant exposure to new information requires continuous adjustments in our actions. To examine how the catecholaminergic system may influence how we structure the continuous stream of information around us into manageable parts, this study makes use of the theory of event segmentation. Building on previous findings, we propose that methylphenidate’s effect on event segmentation behavior depends on learning/prior knowledge and stimulus novelty. In a double-blind, randomized, placebo-controlled crossover study setup, we examined the effect of methylphenidate (0.25 mg/kg) on event segmentation behavior in a group of healthy adult participants (age = 20-30 years). The segmentation of events was examined through a movie paradigm in which participants were asked to segregate the movie’s scenes into meaningful events. The study showed that the effect of methylphenidate on segmentation behavior is reversed depending on prior knowledge and stimulus novelty. When participants were unfamiliar with the task, methylphenidate increased segmentation behavior as the novelty of the stimulus increased. Conversely, where stimuli were familiar, segmentation behavior decreased. The study indicates that the catecholaminergic effect on the segregation of continuous events function varies as a function of prior learning and knowledge and the novelty of the inputs.