Abstract
<p>Working memory maintains information for ongoing processing. Concurrent maintenance andprocessing often incur a cost: Processing can impair memory, and memory load can slowprocessing responses. Such costs in complex-span tasks are often interpreted as shared-resourcecompetition. Alternatively, these costs may arise when processing requires additional informationto be encoded into working memory. Across three experiments, we tested these accounts with acomplex-span paradigm separating processing demand from encoding additional information.Participants remembered novel objects while performing no processing, a constant response, asize judgment on each object against a constant reference, or a size judgment against a changingreference. Memory accuracy declined primarily when processing introduced a changing referenceobject, not when processing demand increased alone. Memory load did not progressively impairprocessing. These findings suggest that maintenance and processing are not generally constrainedby a shared resource; memory costs instead depend on whether processing introduces additionalrepresentations.</p>