Empirical evidence has suggested two independent retrieval processes, intentional recollection and automatic process based on familiarity, operate in retrieving long-term memory. Yonelinas (1994) and Wixted (2007) proposed different models describing the relationship between recollection and familiarity: the dual process signal detection (DPSD) model and the unequal variance signal detection (UVSD) model. The major difference between these two models is the purity of processes. In the DPSD model, recollection and familiarity do not contribute to a single retrieval performance. In contrast, UVSD model suggests that the two processes are simultaneously used while retrieving. The phenomenon change blindness has revealed that the visual information around us is not always encoded or functional available. Thus, the change detection paradigm has been widely used as an indirect method to measure whether visual information is functional available in visual working memory. Previous studies have shown that recognition of pre-change objects is worse than recognition of a post-change object (Beck & Levin, 2003; Mitroff, Simons, & Levin, 2004). However, the memory retrieval process underlying change detection, or visual working memory, has not yet been exhaustively discussed. In this study, we investigated different retrieval processes involved in recognizing a pre-change object after change detection and the purity of processes in the retrieval process. We adopted a Bayesian analysis to estimate the proportion of each process involved in recognition under successful and failed change detection. Our results showed that the UVSD model provides a better fit than the DPSD, suggesting the simultaneity of two processes in retrieving visual working memory. Moreover, the mean parameter value of recollection was higher under successful detection than detection failure. In contrast, there was no difference in familiarity between successful and failed change detection. Recollection is involved in successful change detection.