Objective: Deficits in multiple aspects of attention are a hallmark of the cognitive impairments found with neurofibromatosis type I (NF1). Given, however, that some attention components are hierarchically organized, it is possible that sustained attention, flexibility, and resistance to interference deficits observed in NF1 may be because of weakened lower order attention components. This study investigated the state of these low-level components in NF1. Method: Twenty participants with NF1 (ages 7-13) and 20 matched controls participated in a visual task. They were required to locate a target as quickly and as accurately as possible and to ignore a potential distractor that could appear either before, at the same time, or after the target. Response times (RTs) were collected, and indices of alerting (i.e., reactivity to warning signals), distraction, and interruption (i.e., reactivity to signals appearing during attentive processing) were computed. Results: The amplitude of the indices differed between the groups, F(2, 76) = 3.1, p < .05. No difference was found with alerting (p < .85) or distraction (p < .84), but the interruption index was higher in the NF1 group than the controls (p < .043). Conclusions: Elementary components on which more complex attention processes are based are not all ok in NF1. It is suggested that overreactivity to and longer inspection of visual signals occurring outside the current focus of attention characterizes NF1 and that this might be partially responsible for focus of attention instability and lower interference resistance in NF1.