Inhibition of related abstract shapes during long-term memory

During long-term memory retrieval, inhibition is thought to suppress competing information. Using a novel distorted-item paradigm, we previously reported evidence for the inhibition of related faces during retrieval of previously studied faces. In the present study, a similar paradigm was used to investigate inhibition during memory for abstract shapes, where participants were first asked to remember shapes during the study phase. Then, during the test phase, old, related, and new shapes were presented and participants made "old"-"new" recognition judgments. Related items were created by distorting shapes along a continuum. We found evidence of memory inhibition for related items as there was a lower "old" response rate for distantly related items than new items. A control and follow-up experiment showed that the effects were not due to perceptual differences or a recall-to-reject strategy. These findings indicate that memory inhibition effects during our distorted-item paradigm extend to other stimulus categories.