Familiarity increases the number of remembered Pok,mon in visual short-term memory

Long-term memory (LTM) can influence many aspects of short-term memory (STM), including increased STM span. However, it is unclear whether LTM enhances the quantitative or qualitative aspect of STM. That is, do we retain a larger number of representations or more precise representations in STM for familiar stimuli than unfamiliar stimuli? This study took advantage of participants' prior rich multimedia experience with Pok,mon, without investing on laboratory training to examine how prior LTM influenced visual STM. In a Pok,mon visual STM change detection task, participants remembered more first-generation Pok,mon characters that they were more familiar with than recent-generation Pok,mon characters that they were less familiar with. No significant difference in memory quality was found when quantitative and qualitative effects of LTM were isolated using receiver operating characteristic (ROC) analyses. Critically, these effects were absent in participants who were unfamiliar with first-generation Pok,mon. Furthermore, several alternative interpretations were ruled out, including general video-gaming experience, subjective Pok,mon preference, and verbal encoding. Together, these results demonstrated a strong link between prior stimulus familiarity in LTM and visual STM storage capacity.