Previous research often revealed detrimental effects of seductive details on learning with multimedia instruction, but there are mixed findings regarding how to best explain these detrimental effects. We investigated whether the detrimental effects of seductive details are mainly mediated by the cognitive processes of diversion (deeper processing of seductive details rather than pertinent content) or disruption (unsuccessful attempts to integrate seductive details with pertinent content) by assessing the effects of instructional prompts. In an online learning experiment, participants (N = 247) learned either without seductive details (control condition) or with seductive details in one of three conditions: Participants received either a prompt informing them about the irrelevance of seductive details (irrelevance-prompt), a prompt to process seductive details and pertinent content separately (separation-prompt), or no prompt within their task instruction. We assessed recall and transfer of knowledge as dependent variables. Supporting the diversion hypothesis, participants in the no-prompt condition regarded seductive details as more relevant and consequently spent more time processing them compared to participants in the irrelevance-prompt condition, which negatively influenced their recall performance. Against the disruption hypothesis, participants in the no-prompt condition reported lower integration avoidance between seductive details and pertinent content compared to participants in the separation-prompt condition, but this led to better rather than worse transfer performance. Our results thus suggest diversion, and not disruption, to be the main process driving the seductive details effect. Reducing the details’ diverting potential seems a good way to deal with seductive details in instruction.