Does recognition memory rely on discrete recollection, continuous evidence, or both? Is continuous evidence sensitive to only the recency and duration of study (familiarity), or is it also sensitive to details of the study episode? Dual process theories assume recognition is based on recollection and familiarity, with only recollection providing knowledge about study details. Single process theories assume a single continuous evidence dimension that can provide information about familiarity and details. We replicated list (Yonelinas, 1994) and plural (Rotello, Macmillan, & Van Tassel, 2000) discrimination experiments requiring knowledge of details to discriminate targets from similar non-targets. We also ran modified versions of these experiments aiming to increase recollection by removing non-targets that could be discriminated by familiarity alone. Single process models provided the best trade-off between goodness-of-fit and model complexity and dual process models were able to account for the data only when they incorporated continuous evidence sensitive to details.