Strategic trade-offs between quantity and quality in working memory.

Is working memory capacity determined by an immutable limit-for example, 4 memory storage slots? The fact that performance is typically unaffected by task instructions has been taken as support for such structural models of memory. Here, we modified a standard working memory task to incentivize participants to remember more items. Participants were asked to remember a set of colors over a short retention interval. In 1 condition, participants reported a random item's color using a color wheel. In the modified task, participants responded to all items and their response was only considered correct if all responses were on the correct half of the color wheel. We looked for a trade-off between quantity and quality-participants storing more items, but less precisely, when required to report them all. This trade-off was observed when tasks were blocked and when task-type was cued after encoding, but not when task-type was cued during the response, suggesting that task differences changed how items were actively encoded and maintained. This strategic control over the contents of working memory challenges models that assume inflexible limits on memory storage. (PsycINFO Database Record (c) 2016 APA, all rights reserved).