The position of an item in a list affects how well users remember it. Hermann Ebbinghaus documented the serial position effect in the 1880s through his systematic self-experiments on memory and forgetting. The primacy effect describes enhanced recall for items at the beginning of a list, because they have had time to be rehearsed and transferred to long-term memory. The recency effect describes enhanced recall for items at the end, because they are still active in working memory at the time of recall. Items in the middle of a list are most susceptible to forgetting. This U-shaped recall curve has been replicated across hundreds of studies with great consistency.