Abstract
Redundant displays, those that display the same message via multiple sensory channels, are widely accept-ed as beneficial based on the idea that redundancy offers the potential to effectively distribute processing resources and thus avoid the overload of a high-demand processing channel. While some studies have found performance gains with use of redundant displays, others have shown performance costs. This study investigated whether redundancy in a “multi-code” display – which allows message decoding by engaging either spatial or nonspatial processing resources – would produce redundancy gains or costs under varied concurrent task processing requirements. Results showed dual-task performance was worse when tasks re-quired the same processing code. Redundantly-encoded signals displayed promise for reducing processing interference, a performance gain, but may also negatively affect performance due to a higher overall pro-cessing load. The findings illustrate the effects of processing code redundancy on multitasking performance and add to the body of knowledge in information processing.