Background: Event segmentation, the cognitive process of parsing continuous experiences into discrete events, plays a fundamental role in how humans perceive and interact with their environment. Guided by Event Segmentation Theory, this study investigates the modulation of event segmentation by the catecholaminergic system by methylphenidate (MPH). Methods: Healthy adult participants (N= 52) engaged in a double-blind, counter-balanced, placebo-controlled experiment in which they watched a movie and identified event boundaries under placebo and MPH conditions. Results: With the same information given, MPH increased the likelihood that the information was considered meaningful. Crucially, the number of situational changes and participant's prior experience had an interactive effect on the probability of event segmentation. There was a stronger relationship between environmental information and segmentation probability when catecholaminergic levels were elevated by MPH in addition to previous experience. Conclusions: The catecholaminergic system modulates how incoming information is segmented to build meaningful episodes. Prior experience supports the effects of MPH to unfold. These findings underscore the complex interplay between neurochemical modulation and cognitive processes involved in event perception.