It is possible that statistical learning (SL) plays a role in almost every mental activity. Indeed, research on SL has grown rapidly over recent decades in an effort to better understand perception and cognition. Yet, there remain gaps in our understanding of how SL operates, in particular with regard to its (im)mutability. Here, we investigated whether participant-related variables (such as age) and task-related variables (such as speed of stimulus presentation) affect visual statistical learning (VSL) in typically developing children. We tested 183 participants ranging in age from 5 to 12 years and compared three speeds of presentation (using stimulus durations of 800, 400 and 200 msecs). A multiple regression analysis revealed significant effects of both age and speed of presentation--after attention during familiarization and gender had been taken into consideration. VSL followed a developmental trajectory whereby learning increased with age. The amount of learning increased with longer presentation times (as shown by Turk-Browne, Junge & Scholl, 2005, in their study of adults). There was no significant interaction between the two variables. These findings assist in elucidating the nature of statistical learning itself. While statistical learning can be observed in very young children and at remarkably fast presentation times, participant- and task-related variables do impact upon this type of learning. The findings reported here may serve to enhance our understanding of individual differences in the cognitive and perceptual processes that are thought to rely, at least in part, on SL (e.g. language processing and object recognition).