Poster D125, Monday, March 26, 8:00-10:00 am, Exhibit Hall C
Inhibition of distantly related items in long-term memory depends on the number of repetitions at encoding
Cassidy McCarthy1, Brittany M. Jeye, Scott D. Slotnick; 1Boston College
In a previous study, we found that long-term memory inhibition occurred for distantly related items following three repetitions at encoding. Related shapes were constructed by morphing old shapes between 50 to 200% (independent ratings indicated that 100% morphs were perceptually “different” from the corresponding old shapes). The “old” response rate was lower for 200% morphs than for new shapes, which can be attributed to long-term memory inhibition of distantly related items. In the current study, we evaluated whether long-term memory inhibition of related items was affected by the number of times each item was presented during encoding. During encoding, participants were presented with abstract shapes repeated five times. During retrieval, old shapes, related shapes, and new shapes were presented and participants made “old”–“new” recognition judgments. Preliminary analyses revealed that memory representations were very specific, as the “old” response rate was significantly different between old shapes and 50% morphs. However, unlike the inhibition effects that were observed in the three-repetition experiment, there was no difference in the “old” response rate between 200% morphs and new shapes (t < 1). These results suggest that inhibition of distantly related items in long-term memory depends on the number of repetitions at encoding. One explanation for the present null findings is that more deeply encoded items may not require inhibition to distinguish them from related items. In a future study, we will investigate the brain basis of long-term memory inhibition using the same abstract shape paradigm with three repetitions at encoding.
Topic Area: LONG-TERM MEMORY: Episodic