Nee and Jonides argue that short-term memory (STM) is not monolithic, but instead involves multiple processes with different characteristics.  There are frontal selection mechanisms (normally associated with attention), medial temporal binding mechanisms (associated with long-term memory) and synaptic plasticity.  As a result, STM involves a single representation that can be focused on, a set of active representations that focused can be switched to, and passive long-term memory representations with residual traces that can be easily activated.  The authors show how this model can explain many discrepancies across studies.