It would almost seem without question that repetition should be helpful for learning, but researchers have found that if  repetitions are too much and too long (longer than 10 seconds in one paradigm), further repetition caused poorer memory and word retrieval rather than better! From one of the papers below: “Both Experiments 1 and 2 demonstrated a striking and clear violation of the memory benefits typically associated with repetition. Specifically, increasing the rehearsal time of a word did not yield a straightforward monotonic increase in performance on a later free association test; rather, it led to a nonmonotonic effect, with performance initially increasing, but then declining with longer repetition durations.” The reason for this effect is currently being studied, but the researchers speculated that the increased forgetting […]