Testing during study insulates against the buildup of proactive interference

Recent interest in the benefits of retrieval practice on long-term retention—the testing effect—has spawned a considerable amount of research toward understanding the underlying nature of this ubiqui-tous memory phenomenon. Taking a test may benefit retention through both direct means (engaging appropriate retrieval processes) and indirect means (fostering directed study). Here the authors report 4 experiments demonstrating a novel benefit of testing. Extended study sessions cause a buildup of proactive interference, but interpolating tests during the study sequence insulates against this negative influence. These findings highlight a unique benefit of testing and have important implications for study strategies