Biographies and science passages were constructed to provide multiple experience with prior or interpolated passages in retroaction and proaction paradigms. The eighth-grade subjects read 0, 2, or 4 210word articles prior to the original learning article (proactive) or following the original learning article (retroactive). Subjects responded to completion items in an immediate and a delayed (48 hours) posttest. Both retroactive and proactive interference generally increased over time and across the number of prior or interpolated passages. Interpassage intrusions also increased as a function of number of articles and time interval. Performance with biographical and science materials was similar.