The effects of dual-task interference on visual search and verbal memory

The operational costs of multitasking are more pressing given the increase in wearable technologies (head-up displays; HUDs) that facilitate multitasking. Often multitasking comes with performance costs, where the addition of more tasks impairs the performance of the tasks. The current study explored the extent to which multitasking interference can be characterised in simulated environments, as opposed to risky and harsh environments in real operational contexts. Forty-eight participants completed several trials where they performed a visual search task while navigating a simulated environment. There were three conditions: a standalone memory task, a standalone search task, and both tasks simultaneously. Results revealed significant dual-task interference when comparing the dual-task to each of the single-tasks. Results were corroborated by subjective workload and stress metrics. The results could prove useful for designing systems for individuals who routinely multitask in operational environments. Specifically, by furthering the understanding of their performance capabilities and trade-offs due to multitasking. Practitioner summary: Due to the demands of multitasking in operational environments, quantifying the degree of information lost on each task individually will aid in the understanding of the deficits of multitasking performance. This study shows that deficits in multi-tasking (via a HUD) can be understood in simulated environments to a similar degree as real-world tasks.