Jacoby and his colleagues (e.g., L. L. Jacoby, J. P. Toth, & A. P. Yonelinas, 1993) have shown how the mnemonic contributions of conscious recollection and unconscious familiarity can be separated using a process-dissociation procedure based on a comparison of tasks in which consciously recollected material is to be included in vs. excluded from the responses. However, the estimate of unconscious familiarity depends on the assumptions of the model. This article describes a more general class of models in which the ratio of overlap between conscious and unconscious processes remains fixed and shows that this class of models (which includes the redundancy and exclusivity models as extreme cases) yields improbable results.