Image memorability depends on interference in memory

Some experiences are better remembered than others by most people. This inherent characteristic of an event to be remembered or forgotten is known as memorability. However, it is unclear what drives certain experiences to be more memorable than others, and whether all aspects of an experience are better remembered. Interference across experiences is a major barrier that our memory system must overcome, yet we do not know how interference may impact the memorability of our experiences. Exploring this facet of memory may allow us to parse what drives certain experiences to be memorable or forgettable. To this end, we developed a memory task that varied image memorability and image interference during a memory test and measured target recognition - memory for repeated images, and lure discrimination - discernment of similar "lure" images, increasing interference in memory. While effects of memorability were evident for target recognition, the impact of memorability on lure discrimination depended on interference, where images with higher levels of interference did not benefit from memorability compared to lower levels of interference. Furthermore, these effects were time-dependent: memorability impacted memory immediately, but not after a longer time delay. These findings suggest that the concept of memorability depends on how and when memory is measured.