The project uses a mathematical modelling approach to test different theories of explicit (conscious) and implicit (unconscious) memory. Major theories propose that multiple distinct memory systems underlie explicit and implicit memory, however, the use of a mathematical modelling approach by Berry et al. (2012) has led to a different conclusion, and has instead provided evidence for a single-system model. The project will conduct further tests of the model by determining its generalisability to other tasks that prior research suggests will be challenging for it, such as source memory -- the capacity to recall specific information about an item's previous presentation. The primary aim is to determine whether a single memory system or multiple memory systems underlie repetition priming (implicit), recognition, and source memory (both explicit).