The results of Experiment 2 revealed dissociable effects of the list length manipulation across test formats. In both groups, performance in the Forced Choice test was modulated by the number of studied items, whereas performance in the Yes/No test remained stable across list lengths. This observation is consistent with previous work identifying effects of object interference on Forced Choice performance (O’Neil et al., 2015; Watson & Lee, 2013), but not on Yes/No performance (Stark et al., 2015), and lends support to the proposal that distinct mechanisms support memory performance across test formats. In particular, this observation suggests that Forced Choice performance is more directly related to the availability of object information, and therefore affected by the presence of interference from increased exposure to objects sharing common features. In contrast, Yes/No performance may be constrained by one’s ability to successfully execute recollection-based retrieval processes, which may place an upper boundary on performance. Similarly, previous work has suggested that familiarity-based memory performance may be more sensitive to the effects of interference than recollection-based memory (Sadeh, Ozubko, Winocur, & Moscovitch, 2016), consistent with the proposal that familiarity and recollection differentially contribute to performance in the Forced Choice and Yes/No test formats, respectively (Migo et al., 2009, 2014; Norman, 2010).